Signal: What is the Phoenix project?
Goldstein: Phoenix is the first of the NASA Mars Scout programs. The Scouts are the first of the series of competed missions.
NASA basically has two types of missions: We have missions that they direct, where they define what the science is, and then the mission goes forth and they build it. With the Scout missions, they took a different approach. They go out to the science community and say: OK, what's the latest science that's out there? And we let the PIs — the principal investigators, or the lead scientist from the Mars community — say: What would I like to do to investigate, based on things that we've learned in the past?
The first of those Scout missions was selected in August 2003, and that was Phoenix. We're now getting ready to launch in August of this year. We've leveraged off of additional, or I should say residual, assets that were left over from the Mars Œ01 Lander that never flew, and we're going to go to the northern plains of Mars and dig into the ice that was discovered by the Odyssey (satellite) mission, which is in orbit around Mars right now.
Signal: You're going to explore the north pole of Mars?
Goldstein: Well, the northern poles — about the latitude of Greenland on Earth, would be a good analogy. That's not exactly up at the pole.
The Odyssey orbiter that was launched in 2001 discovered that as far south as about 65 degrees south of approximately Greenland, within about a half-meter of the top surface is actual ice. It's pretty uniform around the whole planet.
Signal: H20? Water ice?
Goldstein: Water ice. And I think as everybody knows, where there's water on Earth, there's pretty much life. So the whole concept for Phoenix was to go down, land in that area, dig into the ice, and investigate what's inside of it.
Signal: The Mars Polar Lander disappeared in 1999 before it ever reached the planet. Is there a lot riding on this mission — sort of Polar Lander 2?
Goldstein: Well, it's "Polar Lander revisited," but Polar Lander with a lot of lessons learned.
We started this mission with a whole litany of things that were found by two review boards, one of which was what they call the Failure Review Board, that basically itemized some(thing) on the order of 10 or 15, maybe even 20 type of things that could have gone wrong and caused the failure of 1998.
In addition, when they were building the Œ01 Lander they convened another board, called a Return to Flight Board, which had another 20 or so types of failures that could have gone wrong with Œ01, or things that would have to be changed on the Œ01 Lander to certify it for flight.
What we did on Phoenix is, we made sure that as we developed the program, as we built the spacecraft and put the instruments on, we actually retired all of those risks that were identified on those two lists.
But that's not enough. That was a necessary, but not a sufficient condition. We actually have a list now — it's growing; it's on the order of 10 to 15 items — that we basically have discovered and corrected from the Œ98 mission that were not on either of those two lists.
Signal: Do they know exactly what went wrong? That time, the lander had disappeared.
Goldstein: That's correct.
Signal: Do they know why?
Goldstein: Well, one of the unfortunate things about the mishap (with) the Œ98 lander is, there was no communication with the vehicle after it separated on its way to the planet and started to go through what we call EDL — Entry, Descent and Landing. So it was very difficult to diagnose what the failure mode was. One of the things that we were required to do — we have a pretty robust communication channel during EDL, so we can actually tell where we are through the entire phase.
But getting back to it, do we really know what happened? No. There are postulated failure modes. There are several, as I said, in these review board findings, that we had to start the mission, but my belief is several of the things that we found during the development of Phoenix were more likely to be the reasons that the Œ98 mission failed.
I think it's good that we found more. As a matter of fact, when we started the mission, I told the team that if we just retire the risks that were identified by the review boards before us, we hadn't done our job. And I'm pretty proud of the team. They have done a great job, and we got a very long list of other failure modes.
Signal: Since then, there have been some significant successes—
Goldstein: Oh, yeah.
Signal: — landing two Mars Exploration Rovers (MER)... and they were in communication as they were going down, except when they went behind the planet?
Goldstein: Not necessarily behind the planet, but during the EDL phase on MER, we had communication — both direct, back to Earth, as well as, we had a link to the MGS (Mars Global Surveyor satellite), the recently lost MGS mission. Not for the entire entry-descent phase, but we had pretty good communications there. We're trying to repeat that on this mission, as well.
Signal: When do you launch?
Goldstein: We open our launch opportunity on August 3 of this year, so six months.
Signal: Are you using an Atlas 5?
Goldstein: No, we're in a Delta 2. Smaller.
Signal: Which they also used for the Mars Exploration Rovers.
Goldstein: Right. We used two different versions on MER, two different versions of the Delta 2: 7925-H and 7925.
Signal: When the Phoenix lands, is it stationary? Or does it move around like the rovers?
Goldstein: We like to call it "vertical mobility" as opposed to "horizontal mobility." Let me start from here:
(The) Mars Exploration Rovers were going to the equatorial region of Mars to look for the past history of water on the planet. So they were geological stations that would rove around and look at the rocks. They were looking and they were very successful at finding the past history of water.
On Phoenix, we now have direct evidence from the Odyssey spacecraft of where the water is today, so what we're going to do is land in that region and, by digging and going down deeper into the surface of the planet, actually look at the water history as it exists there today, as opposed to the past history.
So no, we don't have mobility going from place to place, but we do have a good amount of what we call "work space." We have a robotic arm that can reach out from the lander itself and dig down into the various areas around the lander and hopefully get to the ice.
Signal: It's got an arm to dig up the dirt—
Goldstein: And the ice.
Signal: How far down can you dig?
Goldstein: The arm is designed to dig down about a meter, which is a little over three feet. We know from the data that we used to design the mission that the ice is, at most ,about a half a meter — a foot and a half below the surface.
We have a scoop at the end of the robotic arm that actually has a little drill — it's kind of like a Dremel tool that actually uses a commercial carbine bit. If we get to a layer or a portion of the ice that's particularly tough, that we can't scrape and get a sample, we'll turn the scoop over, and kind of grind the ice into the scoop.
We then take these shavings, which is basically dirty ice — some of the Mars, what they call "regolith," through the Mars soil, which is kind of overburdened on top of the ice — and deliver it to our in-situ instruments. (They) are instruments that can basically heat up the sample that we take, and measure what the constituent elements are within it. Actually, hopefully, maybe even find some organics, which would be like the Holy Grail of the mission.
Signal: The Phoenix will be taking a chemistry lab with it?
Goldstein: Yes.
Signal: What is it capable of looking for? Would you know an amino acid if you found it?
Goldstein: You'd better ask that of the scientists. I wouldn't know an amino acid from the acid I pour in my pool.
Signal: Would the chemistry set know an amino acid?
Goldstein: I'm pretty sure it might; I don't know. You're asking me a science question. I'm an engineer. But what we are able to do — let me talk to you about the two little chemistry sets.
We actually have two little instruments that are quite powerful in their own right. I'll mention what we call the TEGA first, which stands for the Thermal Evolved Gas Analyzer. The TEGA basically takes little samples of the icy soil and drops them into a little canister. It's kind of like a little oven that's a cylindrical tube that seals itself up. The temperature on Mars at the time, or the temperature of the sample, is about freezing, 32 Fahrenheit, zero Celsius. It can heat it up all the way up to a 1,000 degrees Celsius.
As it does, as you add energy into that little oven, you measure how much energy goes in, and you measure the temperature rise. As the sample changes phase, it goes from solid to liquid and liquid to gas. It sees that energy change, and it can determine from there what's inside of the elements.
Once it gets into the gaseous phase, once it melts it and then vaporizes the sample, those gases then go through some manifolds and into what we call a mass spectrometer that can actually break up the constituent elements.
If you ask me to detail the science of what's an amino acid, what element is what, you're out of my league.
Signal: If you found organic material, would the instruments know it?
Goldstein: Oh, yes. The TEGA would, in particular. The TEGA — we put a lot of effort into keeping TEGA very organically clean. We don't want to get a measurement on Mars that basically is an organic from Earth.
Signal: How do you prevent contamination? How do you not carry terrestrial bacteria aboard the spacecraft?
Goldstein: We take special care. If you saw the room that was developed for the building of the TEGA instruments, you would understand how laborious that activity is. People have to suit up — and you may have seen, for example, the rooms that are built for building microcircuits, semi-conductor microcircuits. It's something on that order. It's a very detailed activity — and a very laborious activity of building and cleaning and baking out and wiping and heating to keep it environmentally clean, and then checking the system before it's put on the vehicle.
Signal: This will be the first time we've actually touched ice on another planet.
Goldstein: That is the intent.
Signal: Photos of the poles show ice literally sitting on the surface, correct?
Goldstein: Some of it is ice. Most of it is CO2. Most of it is carbon dioxide.
Signal: You're pretty confident that where you're going, that's water ice?
Goldstein: That's water ice.
Signal: NASA announced a couple of months ago that signs of current flowing water, or flowing water ice, had been found on Mars. Doesn't liquid water basically evaporate immediately because there's not much of an atmosphere there?
Goldstein: It depends on the temperature and the pressure.
Signal: So if there were liquid water under the surface, would you know it? Would you expect to find liquid water under the surface?
Goldstein: I don't think we would expect to find liquid water under the surface, just merely because of the temperature. At the very warm part of the day, it's below zero anyway, so we wouldn't expect that. It's even colder under the surface, so I don't think that's an expectation.
Signal: Did the mission change at all as a result of the discovery of flowing water?
Goldstein: No, I don't think we changed it at all. Well, I'll say it emphatically: We did not change at all. It just reinforced the importance of the Phoenix mission, the discovery of water — the importance that we know the water is there.
Let me add an interesting twist to this new mission. The Mars Exploration Rovers are now in excess of three years on the planet, and one of the questions I'm normally asked is: Will you last that long? One of the interesting reasons why we won't is, where we're landing — and we're landing right at the very late springtime in the northern hemisphere of Mars — where we're landing, at that time of the Martian year, is not covered with CO2. However, as we get into the winter timeframe, the polar caps ... basically get the CO2 condensed out of the atmosphere, build up and actually creep down south.
So eventually — and we hope to capture this with our cameras — there will be a buildup of CO2 around the floor of the vehicle, and effectively encase us into a cocoon.
Signal: You won't thaw out the next Martian spring?
Goldstein: We may very well. We haven't investigated a Lazarus mode here. I'm sure we'll try, but we haven't done any testing to see how well the vehicle will survive, and all the instruments will survive, after being encased for what would be about 365 days encased in CO2.
Signal: When does it land? When is the Martian spring?
Goldstein: In Earth days, assuming we launch in the first two weeks of our launch opportunity, we'll land on May 25, 2008. And if we slip into the third week of our opportunity, we land on June 6, so it's late next spring. It'll be a very exciting and nerve-wracking time.
Signal: Tell us a little bit about the landing. You're not using the airbags this time, like you did with the Rovers. You're going to have a powered—
Goldstein: Pulse-thrusted descent.
Signal: When was the last time you did that?
Goldstein: Well, the last time we did it successfully was with the Viking.
Signal: That was, like, 30 years ago.
Goldstein: Yes. It was almost exactly 30 years ago.
Now, let me start from approach. We go in what we call a direct entry, so after we launch off of the Delta this summer, we come plummeting into the Martian atmosphere at a meager 12,600 mph — a little faster than your car can do, probably. We have about — I think you may have heard of what we call the "six minutes of hell" on MER, on the rovers; we get an additional minute. We have seven minutes of hell. So, lucky us.
Signal: That's basically when you don't know what's going on?
Goldstein: No, we will. We'll have the communication — and we did on MER, as well. We had communications.
Signal: So describe the "seven minutes of hell."
Goldstein: Well, let's see. We come in at about 12,600 mph, and just like all the missions — Viking, even Œ98 and MER and Pathfinder — we take up most of the energy and most of the velocity with a heat shield. We use the atmospheric drag to slow us down. So that takes us from about 12,600 mph down to about 750 mph — again, very similar to these other missions.
Then we open up our parachute, again also like the other missions, at about 750 mph, and that slows us down; that's about Mach 1.5. That slows us down to about 120 mph.
This is where we kind of diverge from the other missions. On MER and Pathfinder, we had solid rockets that slowed us down even further from that point and then dropped off, opened the airbags and bounced and rolled on the planet. On this mission, after we get down to a velocity of, I think it's about 75 mph, somewhere in that range, we drop out of what we call a backshell. We're riding on a parachute. Then we drop out and we have these thrusters that are on the bottom of the vehicle, that start pulsing and slowing us down to about three meters per second, or about 10 feet per second, before we touch down.
What we're doing is, we're kind of pointing and turning the vehicle so we can optimize where our solar rays are, so we can get the most energy while we're on the surface as we're slowing down, and pinpointing ourselves to the planet.
Signal: How does it right itself?
Goldstein: Well, first of all, inside the vehicle we have what we call an Inertial Measurement Unit; it's gyros and accelorometers that we can basically tell what our orientation is, relative to the surface. We actually know what angle we want to land on, because we know where the sun rises and sets on the planet and we know where our solar rays are. We want to maximize that exposure.
So as we're coming down, we'll use our thrusters to turn ourselves and orient ourselves in the most optimal position to basically get within some range of where the sun would go over the solar rays.
Signal: Are you sure you're landing in a flat plain?
Goldstein: Well, that's an interesting question. That is, as a matter of fact, an excellent question. Back in October, you may have heard of the Mars Reconnaissance Orbiter that went into orbit — I think it was last March, if I remember correctly. They have an instrument on that vehicle called HiRISE (High Resolution Imaging Science Experiment), which is a very high-resolution camera.
We had originally selected a target landing site on one side of the planet, and HiRISE effectively opened our eyes to much higher-resolution imaging than we had seen before, and we were rather shocked and scared of all the boulders and rocks.
Signal: There were jagged rocks or something?
Goldstein: Oh, yeah. So it was a scary time, around Halloween.
However, Mars is a big place, and as I said, the water up in that latitude band is pretty much uniform around the planet, so we had a lot of places we can look at. We effectively took some other data that we had of the planet and said: OK, we feel that the rock density will be lower over here.
The happy ending of this story — and as a matter of fact, we've just recently concluded another workshop on this — is, we've actually found two very promising sites that are — I don't want to say "devoid" of rocks, but the amount of rocks that are there is considerably less.
Signal: Like a dry lakebed?
Goldstein: Well, "dry" would be bad. Dry would be very bad.
Signal: An icy lakebed.
Goldstein: Yes. The density of rocks is quite sparse.
Signal: Because you only get one shot, right?
Goldstein: You betcha.
Signal: If you land on a jagged rock and you fall over, you're through.
Goldstein: Yes.
Signal: The obvious question is why you're landing this way. The Mars Polar Lander that was lost, used this same kind of descent system; you've had success with dropping things on the planet surface with airbags. Aren't there more moving parts this way? If one thing worked and another thing didn't work, why are you going with this method?
Goldstein: Well, first of all, there are not more moving parts. I think you've seen the animation for the rovers; that was quite a lot of moving parts to get that little piece to point—
Signal: And unfold and deploy.
Goldstein: But your question has to do, I think, mostly with airbags — why are we going away from airbags and landing (this way)? Well, airbags are very robust; there's no doubt about it. That's why they work. However, one of the big problems that we have in landing (this) payload ... is the mass that you have to land. That's one of the big issues we have to deal with.
When you have airbags, the mass increase, the mass that you have to deliver to the planet, scales. So, what I'm trying to say is: As the mass that you send down goes up, the amount of mass of the airbags goes up a lot. On MER, we were pretty much pushing the limit.
Signal: In terms of how big it could be?
Goldstein: Yes. I'm going back in memory, but I think on MER, we were about 100 to 120 kilos of airbags alone, and I think the total landed mass was just a little bit less than 400 (kilos), so almost 25 percent of the mass was taken up just for the airbag system itself.
At some point, when you try to land bigger and bigger elements, you have to get away from airbags. Does this mean this is the best EDL system? Possibly not, but it's the next one we're going to try.
Signal: If we're going to have a sample return mission sometime, we've got to be doing things other than airbags.
Goldstein: Or even bigger than that, when humans go to the planet. I know they made a movie with airbags on humans; that would have been a hell of a ride. Fifty g's is not very survivable.
Signal: When do we get a sample return mission?
Goldstein: That's an excellent question. The Mars program has been doing studies on that for quite some time, and it's not in the near future that I've seen on a program plan. The complexity of doing a sample return mission is enormous. It is absolutely enormous.
Signal: You've got to be able not just to land, but also to take off again—
Goldstein: Yes.
Signal: So you'd be sending a lot more hardware.
Goldstein: Yes. Some of the problems are, not only do you have to land, but you have to decide what sample you want to capture. Do you want to go grab something that's right next to the lander? Do you want to go, as we did with Mars Exploration Rover, find the right sample and say: Hey, that's the one I really wanted to get? So I'm going to have to have some mobility to go out and get it, bring it back, launch it either into orbit around Mars or directly to Earth, who knows? The complexity there is just severe.
Signal: Tell us about Barry Goldstein. How long have you been doing this?
Goldstein: JPL? I've been at JPL since July 1982. Almost 25 years.
Signal: What projects have you worked on?
Goldstein: Well let's see. I started in 1982; I started working on the Galileo Project. It was the Jupiter orbiter, and I worked in what we called the attitude and articulation control subsystem, which was a lot of fun. It was a great training ground for engineers. We get to play with electronics, software, gyros, actuators — which are basically motors that move the spacecraft — celestial censors, things that look at the stars to determine where you are during cruise and in orbit. A lot of fun. It was a great place to learn. It was a wonderful place to learn. So I worked on that for years.
Oh, gosh. I worked on Cassini, worked on several of the Mars programs recently; it must have been since 1996 I've been working on Mars mission. In 1998 I worked on the payload. It has kind of come full circle, actually. I was the chief engineer for the payload that was lost on the 1998 lander mission, and then moved over to work with what eventually became MER with Steve Squires, the co-PI, and just marching through the Mars program recently.
Signal: How many people are assigned to the Phoenix project?
Goldstein: Directly we have about 270 now; that doesn't count some of the subcontractors. That's between JPL, the University of Arizona — which is the home institution of our principal investigator — and Lockheed-Martin Corp. in Denver, which is building the spacecraft.
Signal: Does the University of Arizona have anything to do with the reason it's called Phoenix?
Goldstein: It's kind of a joke, actually, because the University of Arizona is in Tucson, and they have a unique rivalry — well, maybe not so unique; they have a rivalry with Arizona State, which is in Phoenix. But "Phoenix" was chosen basically to show the rising from the ashes of the Œ01 Lander. So it was kind of a metaphor.
Signal: A metaphor for the lost lander?
Goldstein: It is a metaphor. Yes, it is. And the payload that was lost, as well.
Signal: What brought you to Santa Clarita?
Goldstein: Better schools for my kids, less traffic — ha, ha — back then, in 1994. Not the same anymore. Better value for a home. And a nicer community. It's been all that.
Signal: We look forward to having you back after the Phoenix lands.
Goldstein: Oh, boy. If I have any fingernails left at the time. It's going to be quite a challenge.
Signal: What will you be doing the next six months?
Goldstein: Well, right now, we put most of the spacecraft together. There are a few elements that we have yet to bolt onto it. We've been having some trouble with our landing radar, but we're beyond that now; we have to get it completed, and we'll integrate that.
We've gone through an environmental test, where we take the spacecraft in its cruise configuration and put it into a thermal chamber. We've simulated the entire cruise and the entry, descent and landing phase for the vehicle.
Late in February we have the lander in its full surface configuration, and we'll do another suite of thermal tests in a big chamber to basically exercise the payload as it'll see and basically go through the Mars environment.
Then we'll button it back up, ship it back to the Cape, go to Kennedy. I'll be leaving in May to spend the next three months in Florida, and then go through another series of tests. Make sure everything's ready to go, and then make it to the third stage of the rocket, and Aug. 3, off she goes.
Signal: So what do you think? Is the place you're landing our best bet for finding organic material?
Goldstein: Oh, gosh. I leave those kinds of questions to the scientists. I won't even speculate. I could hope. It would make quite a splash, no pun intended — it would make quite a splash if we found organics.
See this interview in its entirety today at 8:30 a.m., and watch for another "Newsmaker of the Week" on Wednesday at 9:30 p.m. on SCVTV Channel 20, available to Time Warner Cable subscribers throughout the Santa Clarita Valley.
