Human-Tended Experiments

by edward wright

The OSIRS-REx mission, developed by the University of Arizona’s Lunar and Planetary Laboratory, NASA Goddard Space Flight Center, and Lockheed Martin Space Systems, is scheduled for launch in 2016.

This asteroid sample-return mission is interesting for a number of reasons. OSIRIS-REx stands for Origins, Spectral Interpretation, Resource Identification, and Security – Regolith Explorer. This marks the first time that resource prospecting and planetary defense have been prominently highlighted, along with science, as part of a NASA unmanned space mission.

Also interesting is the way OSIRIS-REx team members have tested their experiments in a low-gravity environment.

Last fall, NASA’s Reduced Gravity Office flew the OSIRIS-REx Low-Gravity Regolith Sampling Tests on NASA’s C-9 “Weightless Wonder.” OSIRIS-REx Science Team members Dante Lauretta, Bill Boynton, Beau Bierhaus, and Scott Messenger donned flight suits, along with Lockheed Martin engineers Joe Vellinga, David Wurts, Kevin Payne, James Harris and Tony Siderius for a series of five flights conducted between October 16 and October 18, 2012. Science Team Member Keiko Nakamura-Messenger supplied ground support for the flights.

The Weightless Wonder pilots flew a very-low positive-gee trajectory to test the Touch-And-Go-Sample-Acquisition-Mechanism being developed by Lockheed Martin.

The team conducted one flight on the first day and two flights on each succeeding day. For each flight, two team members remained on the ground to review the results of previous tests and prepare for the next flight.

This test campaign shows the utility of human-tended flight experiments in developing instruments and equipment for space-science missions. Team members noted that their experiment preparations were complicated by the fact that the Weightless Wonder only gave them 14 seconds of ultra-low gravity. In the future, suborbital spacecraft will be able to provide researchers with longer periods of low- and microgravity.

Here’s another example showing the utility of human-tended experiments on parabolic flights for technology development. This time, it’s low-cost CubeSat hardware.

Cadets at the US Air Force Academy are developing an innovative space-based solar telescope called FalconSAT-7.

Instead of a primary lens or mirror, FalconSAT-7 uses a 0.2-meter membrane called a photon sieve. Millions of tiny holes in the sieve focus the light through difraction. The photon sieve, which is less expensive to fabricate than a lens or mirror, can be folded into a compact, lightweight package for launch.

The FalconSAT-7 mission, scheduled for launch in 2014, will be the first time this technology has been tested in space.

“If we can demonstrate that this works, use of a photon sieve opens up the possibility of putting larger telescopes on small satellites,” said Dr. Geoff McHarg, director of the Academy’s Space Physics and Atmospheric Research Center. “This is critical for both NASA and the DoD because the resolution of a telescope is dictated by the size of the primary optic. Traditional space-based telescope optics are limited to the size of the host spacecraft. For instance, the Hubble Space Telescope… had to fit inside the Space Shuttle. NASA would have made a larger Hubble if they would have had a larger spacecraft to launch it.”

Last summer, Air Force Academy researchers tested the photon-sieve deployment mechanism on a parabolic microgravity flight. On August 26, Dr. McHarg took off on Zero-G Corporation’s Boeing 727, G Force One, on a flight chartered by NASA’s Reduced Gravity Research Program. Also onboard were 2nd Lt. Samantha Latch, Trey Quiller, Dr. Michael Dearborn, and Cadet 1st Class Heather Nelson.

Cadet Nelson said, “The Zero-G experience is unlike anything you can possibly describe to someone who has only ever experienced a 1-g environment. For the first parabolas, they have you lay back on your back so your inner ear has a better chance to adjust. When you hit the 1.8-g pullouts you feel like you are being pushed into the floor of the plane — but not like you are being pressed, more like you sink in farther because you weigh more. When you hit the 0-g portions you just float off the floor, it’s sort of like doing a deadman’s float in a pool.”

After acclimating to the changes in gravity, the team successfully tested the deployment mechanism, as shown in the following video.

An even wider range of human-tended technology experiments will be possible in the future when suborbital spacecraft carry out parabolic flights to higher altitudes, allowing longer periods of microgravity.

We hope that those who doubt the utility of human-tended experiments and suborbital spacecraft for scientific research are paying attention.

Edward Wright is chairman of the United States Rocket Academy and project manager of Citizens in Space. You can find more articles by Mr. Wright at the Citizens in Space web site.

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