Tuesday, November 6, 2007

SpaceDev Completes Milestone Under NASA Space Act Agreement

SpaceDev recently completed its first milestone under the Space Act Agreement that it signed with NASA in June 2007. This significant first milestone is to define the outer mold line (OML) of the SpaceDev Dream Chaser space vehicle. The SpaceDev team generated a surface model that will be used for future analysis, subscale flight test modeling, and full scale tooling of the Dream Chaser flight vehicle. The Dream Chaser OML surface model was derived from digitized scans of the original NASA Langley wind-tunnel tested models, which are currently on loan to SpaceDev.

SpaceDev entered into the Space Act Agreement with NASA's Johnson Space Center to facilitate its development of reliable, safe and affordable transportation of passengers and cargo to and from Earth orbit. As part of the agreement, NASA is providing support regarding commercial vehicle requirements for rendezvous and docking with the ISS as well as ongoing regularly scheduled technical exchange.

"The completion of this initial milestone demonstrates the value of the NASA Space Act Agreement program and how well the SpaceDev and NASA teams are working together to forward the SpaceDev Dream Chaser space system," said Mark N. Sirangelo, SpaceDev's Chairman and Chief Executive Officer. Mr. Sirangelo continued, "SpaceDev is proud to have completed a significant technical milestone and we are proceeding forward on schedule with our program."

The SpaceDev Dream Chaser space vehicle is a derivative of the HL-20 Launch System developed by NASA Langley. The vehicle has on-board propulsion utilizing SpaceDev's patented hybrid motor technology. This unique space transportation system is designed to effectively, reliably and safely carry crew/passengers and cargo in both the suborbital and orbital flight regimes. The SpaceDev Dream Chaser space vehicle can be adapted to various mission configurations including carrying up to six passengers, a combination of passengers and cargo, or a maximized cargo configuration. It is a piloted space solution which launches vertically and lands horizontally on conventional runways. Initial flight demonstrations are scheduled in 2009.

Does Russia Have A Nuclear Engine Advantage

Nuclear rocket engines for manned missions to Mars were actively developed both in the Soviet Union and the United States back in 1960-1970, but the work was stopped before the projects got off the ground.

Plasma and ionic electric jet engines are even more economical and "swift." In them a stream of charged particles is whisked to high velocities by means of an electromagnetic field, almost as in a charged particle accelerator.

Another factor increasing their thrust is the capacity of the equipment creating the field and speeding up the particles.

Russia's experience in developing and operating power reactors in space is unique. From 1970-1988, Russia launched a total of 32 spacecraft with nuclear propulsion units and thermo-electric converters of 3 kilowatts and 5 kilowatts capacity.

Most of these vehicles performed reconnaissance operations and remained in orbit in an activated state for several months at a time.

By comparison, America had only one such craft, with a SNAP 10A nuclear reactor and a 0.5 kW thermo-electric power converter, which was launched in 1965. It did not survive long, lasting a mere 43 days and is now part of the space junk orbiting Earth.

Then the efforts became pure research and did not resume until 2002.

Russia is also an expert at making the so-called stationary plasma engines, which have a thrust one order of magnitude greater than the traditional chemical ones. Their first space tests were carried out in 1972 on the Russian Meteor weather satellite, and the regular operation of serially made vehicles began in 1982 on geostationary satellites to correct their orbits.

At present, practically all countries, including the leading space powers, are making active use of various types of Russian-designed electric jet engines. The power of these engines is such that they can adjust the orbit both in longitude and inclination.

Additionally, they can make inter-orbital jumps along energetically optimal multi-revolution trajectories. For example, they can move from a low orbit to a geostationary one and they also serve as a vehicle for interplanetary travel.

In preparing the manned expedition to Mars, the developers considered many options: liquid rocket engines burning oxygen and hydrogen; nuclear rocket engines with liquid hydrogen as a working agent; and a nuclear and a solar installation to power electric jet engines.

For the core equipment they selected the solar-powered unit with thin-film elements based on amorphous silicon.

As a prospective alternative, consideration is also being given to a nuclear power unit as it is developed to reach an operating stage. The main problem in using such units is nuclear and radiation safety during every stage of operation, including emergencies, which requires further research.

Preoccupied with the nuts and bolts of the interplanetary ship and its propulsion, people tend to forget about many other problems, including physiological and psychological ones.

These and other problems must be addressed before humans set out on an interplanetary journey, but that is the subject for a separate discussion.

Chang'e-1 Enters Lunar Orbit

Chinese space officials announced that their Chang'e-1 spacecraft entered lunar orbit on Monday, completing a new milestone in the country's goals of space exploration. The spacecraft is scheduled to begin scanning the lunar surface on Wednesday, but first, it has to complete two additional braking maneuvers.

Mission controllers gave the command at 11:15 local time from the Beijing Aerospace Control Center (BACC) for Chang'e-1 to make its braking maneuver - when it was 300 km from the Moon. It completed the maneuver 22 minutes later, entering a true circumlunar orbit.

This braking maneuver was critical. If it braked too early, the probe wouldn't have been captured by the Moon's gravity, and it would have drifted off into space. If it braked too late, it would have just crashed onto the lunar surface.

The spacecraft's speed was slowed from 2.3 km/second to 1.9 km/second. It's now traveling in a 12-hour elliptical orbit around the Moon, getting as close as 200 km above the surface, and then swinging out to 8,600 km.

Two more braking maneuvers are planned to lower its orbit; one on November 6th, and another on the 7th. When it's all said and done, Chang'e-1 will be going a mere 1.59 km/second, in a 127-minute orbit. It will then begin its science operations.

If all goes well, Chang'e-1 will provide detailed images and data on the lunar surface. China has announced their plans to send a robotic lander to the Moon by 2012 years, and humans within 15 years.

It should remain in lunar orbit for about a year.