For the past several weeks I have been sorting through my files. It's a voyage of rediscovery. Consider, for example, the image at the top of this post; I had completely forgotten it until I stumbled upon the hardcopy yesterday. Taken by an unidentified NASA photographer in 1997, it shows a space suit test subject on board a KC-135 "Vomit Comet" aircraft preparing to step on a cardboard model of the Sojourner Mars rover.
The actual Sojourner rover was a little larger than this caricature. When it stood up on Mars in July 1997, it measured rough 30 centimeters tall, 60 centimeters long, and 45 centimeters wide. It had a mass of 10.6 kilograms.
The space suit the unidentified suit test subject wears is a prototype design with fabric (soft) arms and legs and metal and plastic (hard) shoulder, hips, head covering, and torso. Its hip and shoulder joints slide on bearings. The test subject stands on a simulated Mars landscape made of painted molded foam on plywood.
For the series of tests under way when this picture was taken, the KC-135 flew parabolas, much as it did when it was used for weightless training, but it flew parabolas designed to produce brief periods of Mars gravity (roughly one-third of Earth gravity). The idea was to test the suit, which was heavy and cumbersome on Earth, in conditions as similar to those on Mars as possible.
Exploring robots have gone from strength to strength since this photo was taken; human explorers, not so much. The reasons are not hard to fathom: robots are much cheaper than astronauts, though arguably less capable. Astronauts are more capable than robots, yet are fragile, with so many requirements for survival and risk avoidance that their missions tend to be very expensive.
Some long-time readers of Beyond Apollo will already understand my position vis-a-vis the "humans vs. robots" debate. Basically, I believe that there should be no such debate. Robotic exploration is human exploration. The army of people behind every move Curiosity makes on Mars is an army of explorers, even if not one of them ever dons a space suit.
Similarly, human exploration is robotic exploration. Astronauts are dependent on machines that transport and support them in the alien environment of space. The operational version of the space suit depicted at the top of this post would have had many essential automated features. The Space Shuttle, though flown by astronauts in certain circumstances, was a robot during the critical phases of ascent and reentry.
The 1997 image above reflects the attitudes of its time. Much has changed in the intervening years. For one thing, robot rovers have grown larger and more capable: an unfriendly astronaut, insecure about his role in the exploration of space, might harm three-meter-long, 899-kilogram Curiosity in any number of ways, but stepping on her would not be an option.
Another thing that is different is that a serious push is underway now to fully meld human and robotic space capabilities. Representative of this is HERRO, a variant of NASA's latest Mars Design Reference Mission, DRA 5.0. HERRO would see human geologists remain safely on board a radiation-shielded spacecraft that would spin end over end to create acceleration that they would feel as gravity. The HERRO spacecraft would orbit close enough to Mars that the radio signal travel time would be negligible, permitting the geologists on board to explore its surface in real-time using sophisticated teloperated robots.
The geologists could, through their capable robotic proxies, wander widely over the martian surface. For them, installed in a teleoperations control booth on board the orbiting HERRO spacecraft, the experience would resemble space-suited exploration, but with fewer risks and greater comfort. A robot hand could become a drill or a chemical sensor with the press of a button.
As one group of teleoperated rovers fell below the HERRO spacecraft's horizon, the geologists would switch to another group at an exploration site hundreds of kilometers away from the first. They would probably operate in shifts so that teleoperated rovers and teleoperating geologists would be active at all times throughout a stay in Mars orbit that might last more than a year.
The geologists could collect samples and deliver them after a time to one or more pre-landed ascent vehicles. These would launch the samples to the HERRO spacecraft for retrieval. There the geologists would perform a preliminary analysis before packing the samples away for return to Earth.
The HERRO mission would not delay that epochal moment when a human being first places a booted foot in the dust of Mars; it would, in fact, almost certainly advance the piloted Mars landing timetable. A responsible Mars program would see it as an essential interim step. It would decrease uncertainty about piloted Mars mission technologies, much as Apollo 7, 8, 9, and 10 prepared the way for the piloted moon landings that followed. The HERRO spacecraft, or perhaps portions of it, might be reused for piloted Mars landing missions to cut costs.
A HERRO spacecraft and teleoperated robots could make accessible hostile worlds where humans might never set foot. Venus, Io, and Europa spring to mind. Venus has a hot, dense atmosphere. Io and Europa are deep within the dangerous radiation belts of giant Jupiter.
HERRO might prove essential if we take seriously the notion of planetary quarantine. If, for example, we have not satisfactorily answered the question of whether life exists on Mars or Europa, then it is doubtful that we would wish to contaminate either world with Earth microbes. Such contamination is considered all but inevitable after we land humans. HERRO will provide most of the same scientific exploration capabilities as a piloted landing mission while largely avoiding the risk of forward contamination.
There are many good reasons to fly a HERRO-type mission ahead of a piloted Mars landing mission. I plan to write about them in more detail in a forthcoming post. For now, I invite your comments.
