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Thursday, 11 September 2008

More space news-and on bad news

In today's edition:

  1. Launch of Private Rocket Fails; Three Satellites Were Onboard
  2. NASA says liquid confirmed on Saturn's moon Titan
  3. Venus Express to fly closer to Venus

Launch of Private Rocket Fails; Three Satellites Were Onboard

Published: August 3, 2008

A privately funded rocket was lost on its way to space Saturday night, bringing a third failure in a row to an Internet multimillionaire's effort to create a market for low-cost space-delivery.

The accident occurred a little more than two minutes after launch, and the two-stage Falcon 1 rocket appeared to be oscillating before the live signal from an on-board video camera went dead.

"We are hearing from the launch control center that there has been an anomaly on that vehicle," said Max Vozoff, a mission manager and launch commentator for Space Exploration Technologies Corporation, on a webcast of the event soon afterward.

Elon Musk, an Internet entrepreneur, founded the company, known as SpaceX, in 2002 after selling his online payment company, PayPal, to eBay for $1.5 billion. The company, based in Hawthorne, Calif., has been hailed as one of the most promising examples of an entrepreneurial "new space" movement, and has 525 employees.

The rocket was launched from the Kwajalein Atoll in the central Pacific at 11:34 p.m. Eastern time, after several hours of delays and one aborted launch attempt.

The first Falcon 1 launch, in March 2006, failed about a minute into its ascent because of a fuel line leak. A second rocket, launched in March 2007, made it to space but was lost about five minutes after launching.

On this flight, the Falcon carried three small satellites: one, called Trailblazer, for the Department of Defense, which was built as a kind of quick-turnaround demonstration. The two others were for NASA: PRESat, a small automated laboratory, and NanoSail-D, a test of the concept of using sunlight to push a thin solar sail and provide propulsion without propellant.

The rocket was also carrying the ashes of 208 people who had paid to have their remains shot into space, including the astronaut Gordon Cooper and the actor James Doohan, who played Montgomery "Scotty" Scott, the wily engineer on the original "Star Trek" television series. The service is called an "Explorers Flight" by the company that arranges them, Celestis, Inc.

The company is also developing a larger rocket, the Falcon 9, with nine engines in the first stage. That vehicle is intended to provide cargo services to the International Space Station under a contract for NASA after the shuttle program winds down in 2010. SpaceX performed a successful test firing of the Falcon 9 engines at its facilities in McGregor, Tex., last week.

Charles Lurio, an independent space consultant, it should not be surprising to lose single-use rocket vehicles in the early stages of development, because their very design does not allow test flights. "It's all or nothing once it leaves the pad," he said. "But I hope SpaceX keeps trying," he said. "They're very competent people."

In Mr. Musk's statement, he insisted that the company will not be deterred and still has strong support from its backers. "SpaceX will not skip a beat in execution going forward," he said, and added that the fourth flight, currently scheduled to take place in the fourth quarter of the year, and fifth flights are being prepared, and that he has given the go-ahead "to begin fabrication of flight 6."

And, he added, "We are in very good financial basis here. We have the resolve, we have the financial base, and we have the expertise" to identify the problem and go forward. "

In the teleconference, Diane Murphy, the company spokeswoman, said that the mood at the company's headquarters quickly switched from excitement and cheers at the seemingly successful launch to concern and then disappointment. But when Mr. Musk addressed the employees, she said, and told them that the company would move forward with the fourth flight. source

My comment: The major reason why I published this is because of the NANO-sail mission, that I wrote about recently. If you remember, the idea was to test whether it's possible to fly a spacecraft using the Sun's emission. I was very interested in the development of the project. And now, we see it exploding due to the incompetency of those people. I realise test-flights are test flight for the reason they may explode, but still, how could you put a project on a test-flight?! I mean is it sooo cheap to do the spacecraft? Absolutely wrong!

NASA says liquid confirmed on Saturn's moon Titan

Thursday, July 31, 2008 1:34:07 PM
NASA says liquid confirmed on Saturn's moon Titan

At least one of many large, lake-like features on Saturn's moon Titan studied by the international Cassini spacecraft contains liquid hydrocarbons, making it the only body in the solar system besides Earth known to have liquid on its surface, NASA said Wednesday.

Scientists positively identified the presence of ethane, according to a statement from NASA's Jet Propulsion Laboratory in Pasadena, which manages the Cassini mission exploring Saturn, its rings and moons.

Liquid ethane is a component of crude oil.

Cassini has made more than 40 close flybys of Titan, a giant planet-sized satellite of the ringed world.

Scientistshad theorized that Titan might have oceans of methane, ethane and other hydrocarbons, but Cassini found hundreds of dark, lake-like features instead, and it wasn't known at first whether they were liquid or dark, solid material, JPL's statement said.

"This is the first observation that really pins down that Titan has a surface lake filled with liquid," Bob Brown, team leader of Cassini's visual and mapping instrument, said in the statement.

The instrument was used during a December flyby to observe a feature dubbed Ontario Lacus, in the south polar region, that is about 7,800 square miles, slightly larger than North America's Lake Ontario.

Cassini reached Saturn in mid-2004 and at the end of that year launched a probe named Huygens that parachuted to the surface of Titan the following January.

The mission is a project of NASA, the European Space Agency and the Italian Space Agency. source

My comment: Nice collaboration. And it's great to see Titan so useful. I mean we certainly can use its liquids. Not to mention what may swim in those oceans. It's so thrilling!

Venus Express to fly closer to Venus

15 Jul 2008

A series of orbit control manoeuvres (OCMs) is underway to alter the orbit of the Venus Express spacecraft, with the goal of reducing the pericentre altitude to 185 km. These manoeuvres, which began on 13 July, provide new opportunities for scientific observations of regions which have not been probed by the spacecraft so far.

Figure 1. The initial Venus Express orbit (to scale). The eccentric orbit has its pericentre close to Venus's northern pole.

In April 2006, Venus Express successfully entered orbit around Venus. Several manoeuvres over the period 15 April - 6 May 2006 then lowered the spacecraft into its operational orbit: a 24-hour, elliptical, quasi-polar orbit, in which it has been since. The nominal mission of 500 days was successfully completed by the summer of 2007. Venus Express is now in the middle of the extended period of operations that runs up to May 2009.

The highly eccentric orbit takes Venus Express out to 66 000 km from the planet when at apocentre. The pericentre altitude varies between 250 and 400 km due to natural perturbation of the orbit, mainly by the Sun's gravity. Regular corrections to compensate for this perturbation are performed to maintain the pericentre in the desired altitude range.

Over a period of about four weeks, beginning on Sunday 13 July, the pericentre of the orbit is being permanently lowered from its former range of 250-400 km to 185-300 km. The lowering will be done in four steps at one-week intervals. Each step includes two manoeuvres: one at pericentre to raise the apocentre altitude, and one at apocentre during the next orbit to lower the pericentre altitude (for more details see below). The combined effect of each pair of manoeuvres will leave the orbital period largely unchanged.

New Opportunities for Science

The lowering of the pericentre altitude greatly extends the science that can be done with the remote sensing instruments on-board Venus Express. The instruments that benefit the most from the closer proximity to Venus are the magnetometer (MAG) and the Analyser of Space Plasmas and Energetic Atoms (ASPERA). Specifically, after the completion of the manoeuvres:
  • energetic neutral and charged particles can be characterised over a wider range of altitudes and in a different environment than was possible up to now.
  • in-situ studies of the environment will be possible well into the ionosphere. (The base of the ionosphere is at an altitude of ~120 km and varies little with time. The top of the ionosphere is formed by the ionopause – the boundary at which the electron density drops significantly. The altitude of the ionopause does vary with time and lies in the range of about 225-400 km.)
  • a better characterisation of the magnetic field can be performed in the north-polar region (where the pericentre of the spacecraft's orbit lies). It will be possible to study the lower part of the externally induced magnetic field (caused by the passing solar wind carrying the interplanetary magnetic field that interacts with the ionosphere). In addition, at the lowest altitudes a search can be conducted for magnetic fields due to a weak dynamo or to other processes related to the interior of Venus.
  • improved characterisation of lightning events can be performed.

Drag experiment
As a result of lowering the spacecraft's altitude at pericentre, the spacecraft will start to experience drag from the upper atmosphere around the pericentre passages. Although very small, the integrated effect of this drag on the spacecraft orbit is expected to be clearly noticeable below an altitude of ~200 km.

The integrated effect of atmospheric drag can be derived from orbit determinations, based on spacecraft tracking data. To perform these measurements a series of thirteen dedicated passes with the ESA New Norcia ground station and NASA DSN ground stations are scheduled in addition to the normal periods of spacecraft tracking and communication. These extra passes fall in the period between 30 July and 22 August and are performed around the pericentre passages of Venus Express.

At even lower altitudes than those achieved with this pericentre lowering campaign, it would be possible for the spacecraft's accelerometers to directly measure the effects of the atmospheric drag on the spacecraft. This would allow for a more detailed determination of the atmospheric density with altitude. Such operations, however, if performed, still lie beyond the current extended mission (ending May 2009). source

My comment: Ok, this is pretty technical, but still, it's the progress of space industry! Enjoy!

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