 |
|
 |
 advertisement
| |
|
|
|
|
|
NASA Dreams of Jacobs Ladder to Mars
By Andrew Bridges
Pasadena Bureau Chief
posted: 07:00 am ET
06 November 2000
|
- Dr PASADENA, Calif. Rung by rung, NASA hopes to climb to Mars over the next decade with an admittedly less aggressive but what it says is a more realistic program of missions."Youve heard of Stairway to Heaven? This is the ladder to Mars," said Scott Hubbard, NASAs Mars program director. The latest iteration of NASAs campaign to study Mars relaxes the breakneck pace the agency had earlier undertaken. Gone is the plan to dispatch probes two-by-two like animals sent packing onto Noahs Ark to Mars every 26 months.In its stead is a commitment to send but a single spacecraft to Mars during each launch opportunity, alternating at least in the near-term between landers and orbiters. "The program I signed up to may not be too aggressive, but itll be more than view graphs," Ed Weiler, NASAs associate administrator for space science, told SPACE.com before unveiling the new plan. The new plan allows each successive mission to respond to either new discoveries made by previous missions or to their utter failure, a fate that befell both the Mars Climate Orbiter and Mars Polar Lander last year, NASA officials said. 
Under NASA's new Mars exploration plan, the agency will stick with the plan to launch two rovers to the Red Planet in 2003. Steve Squyres, the Cornell University space scientist who is leading the building of the science packages to be carried by dual rovers that will go to Mars in 2003, called that approach the right one."It makes sense," Squyres said. "If you alternate landed and orbital missions, each mission of a given type can benefit from what was learned on the one before." The previous plan, he added, was tagged as "success-oriented." "Thats another way of saying over-optimistic," he said. Gone too is the hell-bent goal of returning a sample of Martian soil and rock to Earth. Scientists hope that such a sample could answer, perhaps once and for all, the question whether Mars harbored life any time in its past or if it still does in the present day. But any Mars sample-return mission has now been pushed back to 2011 or, more realistically, to 2014 at the earliest.That delay worries many Mars scientists, who see samples as the Holy Grail of Red Planet exploration. NASA previously envisioned a 2005 mission to snag perhaps a few pounds of the surface of Mars for return to Earth. "The Mars program needs more dirt," said Chris McKay, a space scientist at NASAs Ames Research Center in Californias Silicon Valley. "Its a great plan, but we need to push harder on getting subsurface samples from just a couple of meters down. That means drilling. Secondly, we have to push harder on getting samples from Mars back here on Earth." ~ For Bruce Jakosky, a University of Colorado, Boulder astrobiologist, the delay pushes any estimated $2 billion sample-return mission too far into the future. "If the first sample-return mission is not until 2014, that is far enough away as to be essentially off the table. Is NASA really saying that we are not able to carry out a sample-return mission at present and should not plan one?" Jakosky said. NASAs Hubbard stresses the slow-down seeks to avoid the strikeouts that marred the agencys last two Mars missions. "What we are doing is following a scientifically driven program rather than go for the home run as quickly as possible," said Hubbard, referring to a Mars sample-return mission. Instead, the new program will lead NASA to pull back and drink in Mars as a whole before undertaking anything as ambitious as sample return. Indeed, the agency will literally do that in 2005, with the launch of a keen-eyed orbiter that could expand scientists view of Mars by revealing the planets surface in unimagined detail detail that rivals the resolution provided by commercial satellites aimed at Earth. NASA can then use the detailed view captured from afar to better target its surface missions, scientists said. "The difference is that NASA has decided to broaden the science of the program to what I call Understand Mars, and thats evident in the reassertion of the importance of orbital science," said Daniel McCleese, chief scientist in the Mars program office at NASAs Jet Propulsion Laboratory. To do so, NASA is inviting into the fold various types of missions that perhaps had gotten the squeeze when the agencys Mars program focused on Mars sample return and the search for life. Among them are Scouts, a catchall name for a class of missions that could include everything from balloons to airplanes to a network of small landers that could carry, for instance, seismometers to measure "marsquakes." Currently, NASAs Discovery Program has in hand various proposals for all three types of missions or instruments."Its goal is to bring in some of those ideas that have percolated around but that have never bubbled to the top," Hubbard said of the Scouts. For scientists like Squyres, that could promise some out-of-the-box approaches to Mars exploration. "I really like the fact that every so often, starting in 2007, there will be opportunities for the Mars science community to competitively propose missions that will use innovative approaches to doing additional science at Mars," Squyres said. "I predict that well get some really exciting stuff out of this part of the program." But scientists like Jakosky fear public interest and support for NASAs Mars program could erode, especially with the drawn-out plan to return Martian samples to Earth. "Im concerned that the intense public interest in the search for life, currently being fueled primarily by the search for extrasolar planets and the potential for life on Mars, will not survive an almost two-decade hiatus before even the first chance of getting an answer," Jakosky said.
|
|
|
|
|
|
 |
|
|
