The Nov. 26 launch of NASA’s most ambitious Mars mission to date was yet another milestone for the Jet Propulsion Laboratory (JPL), which over the decades has distinguished itself for carrying out planetary missions beyond the capabilities of any other institution anywhere.
With the Mars Science Laboratory (MSL), a nuclear-powered, car-sized rover, now on its way to the red planet, the question is what’s next for the legendary JPL, which currently has no large, funded planetary missions on its plate. NASA’s Osiris-Rex asteroid sample-return mission, for example, is led by the agency’s Goddard Space Flight Center in Greenbelt, Md., which in recent years has garnered a larger share of planetary projects.
Ever the optimist, Charles Elachi notes that JPL, which is co-located with and managed by the California Institute of Technology in Pasadena, is building an Earth science satellite and working on designs for an affordable mission to Jupiter’s icy moon Europa. He also is hopeful that NASA will be able to commit to a 2018 mission to Mars with the European Space Agency per a 2009 agreement that is being revisited due to the U.S. funding limitations.
Elachi worries that JPL’s unique capability to land probes on distant planets will be lost should NASA not take a role in the 2018 mission, which would utilize the same entry, descent and landing system that will debut on MSL. He concedes he will get little sleep on the eve of MSL’s scheduled Aug. 6 landing, in which a so-called sky crane system is to lower the rover to the planet’s surface by cable from a hovering spacecraft.
Elachi, who says NASA is enjoying a golden age of planetary exploration, spoke recently with members of the Space News editorial staff.
Now that MSL is on its way to Mars, how many people are coming off of the program?
There were about 600 people for development. For the operation we are going to need about 300 people or about 250.
Are the same people who built MSL doing the operations?
A fair number of them, because you need people who understand the systems, and so on. So you have about 200, 250. And we’re already down to 350 now.
What about the others?
We found positions for the other people. And we have the Soil Moisture Active-Passive satellite — it’s an Earth-orbiting mission, but it’s being built in house. Now, the concern I have is if we don’t have a Mars mission in 2018, then we start losing our capability of doing entry, descent and landing. So really, my concern is not necessarily exactly the number; it’s the capability. Will our nation lose a capability of landing on other planets? JPL is the only team which has done it.
When does NASA need to commit to the 2018 Mars sample-collection mission with the European Space Agency?
I would say to do an ’18 mission, you need to commit in the fiscal year 2013 cycle. So we’ll have to wait and see what the president will submit. If the decision is made by the end of 2012, that still gives us six years to get to it. I’m confident that we can do that because we’re capitalizing a lot on the MSL engineering designs, so the idea would be to use a similar, as a matter of fact almost identical, descent module. The rover would be different, because it’s doing different things, and the payload would be different. But it basically would be the same descent system.
The sky crane seems risky. Was it the really the best mechanism you could come up with?
If you want to land a ton-sized vehicle, you cannot use airbags. We looked at the airbags. But MSL is seven times the size of the Spirit and Opportunity rovers. It’s like 900 kilograms, roughly, versus 200 kilograms or 180 kilograms. After doing a lot of engineering analysis, the smartest engineers who have worked on landings said the sky crane is the best way to do it. Airbags, they become huge. There was no way you could fit them to do that. To go all the way down using propulsion, you have to find a way to drop off the lander. We remember with Spirit and Opportunity that was a big concern: to be able to drive off a platform.
What sort of Europa exploration schemes have you been looking at with NASA having concluded that it cannot afford the $4.7 billion concept that was being studied?
We have been looking at missions which are below $2 billion. Now, they will not do all the science that the big Europa mission will do, but we are looking at three different options.
One is to go in orbit around Jupiter but be in synch with Europa. So every time you orbit, you fly by Europa. So you can do 80, 90 orbits and you can fly by Europa 80, 90 times. So now you’ve avoided the radiation because you are just zooming by Europa and not yet in orbit around it. Another mission we are looking at is taking all of the instruments that absolutely have to be in Europa orbit and put those on a smaller probe; we’ll orbit Jupiter and then we’ll orbit Europa. A third element is to do landers, to basically drop landers.
The point is we have a proof of concept that we can do some major missions to Europa and have a significant amount of the science — not all of the science — for $1.5 billion to $2 billion.
Do you consider $2 billion to be the cost threshold for designation as a flagship-class mission?
My definition of a flagship mission is not really the dollar number, per se. These are missions which do in-depth studies of the planet that they are observing, and they have a multiplicity of instruments which are on that. So I would call Voyager, Cassini, Galileo, Spirit and Opportunity, Hubble; these are my definitions of flagship missions.
What would the Cassini Saturn orbiter mission cost in today’s dollars?
It would be close to $3 billion. Voyager wouldn’t be very much. If you look at Spirit and Opportunity, it would probably be $1.5 billion in today’s dollars. I’m talking everything here: launching them, operating them, the whole thing.
How can flagship missions be justified in the current budgetary environment?
Flagship missions, you do major science with one launch. Smaller missions, you need multiple launches, and the launch is becoming a large cost. I’m concerned both about the selection and the costs of launch. The more money you spend on the launch vehicle, the less money that goes on the missions. That’s what I’m worried about; that’s what lots of people at NASA are worried about.
Somebody at JPL did the calculation recently on how much money goes to the science, percentage-wise, relative to the total cost of the mission. And the flagship missions came way above smaller missions like Discovery- and New Horizon-class missions. If you take a fixed amount of money, flagship missions give you more science than the equivalent amount of smaller missions because of the launch costs. We looked not only at the cost, but how much publication, per dollar, missions generate. It turns out Cassini, Voyager, Hubble are well above the equivalent of the smaller missions.
All NASA science programs are being asked to contribute to fund the overbudget James Webb Space Telescope, on which JPL has a relatively small role. What kind of effect do you expect to feel at JPL?
We have to wait and see what’s in the ’13 budget and beyond. For ’12, the impact was very limited. As you know, there was an increase in the Science Mission Directorate budget that covered a significant part of it. Fundamentally, I support it. Sometimes I have to look at, “What’s the benefit for JPL?” But sometimes, I really ask, “What’s the right thing for the nation?”