By James Oberg
Seven months into its open-ended orbital shakedown cruise, Bigelow Aerospace's inflatable test vehicle Genesis-I is performing smoothly, a company official has advised IEEE Spectrum. As previously reported in this month's issue, the mission was to test variations of spacecraft systems for future vehicles leading to the development of an inhabitable orbital outpost for a wide range of functions, potentially including tourism, in the next decade.
"We have been monitoring all of the onboard systems many times a day," says Jay Ingham, deputy program manager at the Bigelow Aerospace plant, in North Las Vegas, Nev. "We have been very pleased with both the initial operational success, as well as the continued reliability of virtually all of the onboard systems," he continued, in a press statement planned for release on February 14.
Placed in a high-inclination orbit by a commercial Russian rocket, the module's altitude has slipped 6 miles (to 340 miles) under the effects of air drag. "At this point we are predicting that the vehicle will maintain its orbit for well over 10 years," Ingham stated.
"Our avionics and communications to and from the vehicle have operated very well," wrote Ingham. "We communicate with Genesis I several times a day." He added that they planned to do so more frequently as the ground sites in Alaska and Hawaii come online. Ingham acknowledged occasional "minor issues" but stated that they were all "resolved with minor software fixes or adjustments." In particular, he continued, "we have had some problems with a computer that controlled several of the cameras."
One externally caused crisis has occurred, he revealed. "There was a very severe radiation event caused by solar activity on or about the 14th of December," an event that also impacted planned spacewalks for the Space Shuttle mission then docked at the International Space Station. "We did suffer some minor communications problems during and after this period which required us to use our backup systems," he disclosed.
"This problem was remedied with a reset of our primary system," he explained. "This was very encouraging to us that we could survive such an event and recover from it gracefully."
Otherwise, the spacecraft's electrical systems are performing well, Ingham detailed. "We have seen no measurable degradation of the power generating capability of all eight solar arrays," he said. "Our battery has not shown any signs of a loss of capacity, but from our use and recharge cycles we are currently calculating a life span of [more than] seven years." All of the interior electrical systems such as the lights and fans, according to Ingham, "remain in perfect working condition."
Genesis-I is now getting a more active than planned workout because of the delay in the launch of its sister-spacecraft, Genesis-II. Although that vehicle is complete and ready to ship to Russia, the launch provider has delayed flight due to a failure of a similar booster in another commercial attempt last summer. Ingham expects Genesis-I's battery life to be extended beyond seven years once the control center's attention is diverted to newer vehicles.
Particularly crucial is the flight validation of the revolutionary hull design, which uses flexible, expandable materials rather than the traditional "hard shell" of every previous human space vehicle. In theory and in ground testing, the thick multi-layered hull should be much stronger than thin metallic shells—but the design (based on NASA work in the 1990's that was later cancelled) had never been exposed to the actual space environment of vacuum, thermal cycles, solar radiation, and space debris.
Ingham reported that the initial results were very good: "Structurally, Genesis I is in tip-top shape. From pressure data, we can determine that the expandable envelope and pressurized structure remains perfectly intact, and from the numerous exterior photographs we download daily, we cannot detect any degradation of the orbital debris shield or discoloration due to the elevated UV exposure we see in space."
In particular, Genesis-I is holding pressure very well—a sensitive issue since the initial pressurization of the spacecraft did not go smoothly due to a fabrication oversight on the pressurization tank nozzles (not discussed by Ingham, this hiccup has been confirmed by Bigelow Aerospace officials). "Our pressure levels internal to the vehicle have maintained exceptionally well," Ingham announced, "achieving lower leak rates than those that we have tested on the ground."
Ingham described how the interior temperature has varied, but it's well within expected bounds—as cold as 40F, as warm as 90F. Genesis-I has no active thermal control system—no heaters, no coolant loops with external radiators, nothing of that complexity. As a result, "The interior air temperature varies with the quantity of electronics we have operational at any point in time and the amount of sun exposure the vehicle sees." Later vehicles will test active temperature control systems.
The station-wagon-size satellite continues to orbit the Earth, visible at dawn and dusk as a fast-moving, dim, starlike dot (stellar magnitude 3 or 4—binoculars are advisable). Predicted visual passes for any location are available at this site (click on "10 day predictions" for Genesis-I). Follow-on vehicles will be bigger and brighter, thanks to the encouraging results of this groundbreaking (or should I say spacebreaking?) technology demonstration.
James Oberg, today's guest blogger, is a lifelong "space nut" who worked 22 years at NASA Mission Control in Houston. He is the NBC News space analyst and a long-time contributor to IEEE Spectrum. In 1999, he published Space Power Theory for the U.S. Space Command. You can learn more about his work at his Web site.