Dawn Mission Launched to Asteroids

by Paul Gilster on September 27, 2007

Launch of Dawn Mission

Great to see Dawn on its way. The spacecraft lifted off at 11:34 UTC, with signal acquisition just over one hour into the flight. The spacecraft will begin its exploration of Vesta in 2011 and Ceres in 2015, two asteroids that between them have much to tell us about the history of the Solar System. Measurements of shape, surface topography, tectonic history, elemental and mineral composition will be included in a full data acquisition package. Image credit: NASA.

{ 4 comments }

Adam September 27, 2007 at 17:09

Hi Paul

Such a LONG time to wait for results. Our current ion-drives are decidedly under-powered, but they’re the only thing that can give us a multi-object orbital mission.

Two other asteroid/comet missions with multiple targets are Deep Impact and Stardust, which have both been retargetted – Stardust will be flying by Tempel 1 for another look, to check out the crater dug out by Deep Impact. Of course the big difference is that both follow up missions are flybys. No loitering!

We’ve looked at a few ‘roids and comets now – and we’ve seen no trace of ETI activity. Not a big sample, but it does mean the Solar System hasn’t been massively exploited. Though the large scale porosity of some objects does make me wonder.

Marc L September 27, 2007 at 18:05

I watched the event this morning right before I left. It was definitely an exciting event. I don’t understand why the news media was making it sound like we won’t get any results from Dawn until 8 years from now. If it will visit Vesta in 2011, then we truly won’t have to wait that long.

ljk October 10, 2007 at 16:06

CfA Release No.: 2007-23

For Release: Tuesday, October 9, 2007

ASTEROID NAMED IN HONOR OF 50TH ANNIVERSARY OF THE SPACE AGE

In recognition of the 50th anniversary of the start of the Space Age, an
asteroid has been named “Astronautica.” Minor planet number 100,000 (also
known as 1982 SH1) was chosen for this honor because space is defined to
begin at an altitude of 100,000 meters (100 kilometers, or 62 miles) above
Earth’s surface.

“Fifty years ago, a tiny satellite named Sputnik became the world’s first
artificial satellite. It seemed only fitting to commemorate the 50th
anniversary of the dawn of the Space Age in some astronomical way,” said
Brian Marsden, director emeritus of the Minor Planet Center, which is
located at the Smithsonian Astrophysical Observatory in Cambridge, Mass.

The Minor Planet Center serves as a clearinghouse for asteroid discoveries
and assigns numbers in the order that observations are received and
catalogued. Astronautica received the number 100,000 in October 2005. It was
discovered by astronomer Jim Gibson of Palomar Observatory on September 28,
1982, only days before the 25th anniversary of Sputnik.

“Astronautica is not a particularly unusual object,” Marsden said. “It just
happened to be the 100,000th entry into our database.”

The name was approved by the International Astronomical Union’s Committee on
Small Body Nomenclature, of which Marsden is a member. Currently, 14,077
asteroids have names while a total of 164,612 asteroids have been identified
and numbered.

“Typically the discoverer names the asteroid, but the committee sometimes
takes the initiative for special numbers,” explained Marsden. “October 4,
2007 was an important anniversary, and we felt it was right to recognize it
this way. We wanted a name with a broad international appeal, so we chose
‘Astronautica,’ which comes from the Latin for ‘star sailor.’”

Astronautica is a space rock about a mile in size. Due to its small size and
low mass, it is undoubtedly a misshapen lump like many asteroids.

Its orbit lies between the orbits of Mars and Jupiter. It circles the Sun at
an average distance of about 175 million miles. A “year’ on Astronautica
lasts around 940 days-the equivalent of 2.6 Earth years.

Astronauts may visit Astronautica some day, using tethers to anchor
themselves to the surface in the asteroid’s weak gravity. However, that day
is far in the future. Space travelers are likely to head to near-Earth
objects like Eros well before making the long trip to the asteroid belt.

“Perhaps on the 100th anniversary of Sputnik, a tour group will visit
Astronautica,” Marsden grinned.

An orbital diagram of (100000) Astronautica is available online at
http://www.cfa.harvard.edu/press/2007/pr200723_images.html

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for
Astrophysics (CfA) is a joint collaboration between the Smithsonian
Astrophysical Observatory and the Harvard College Observatory. CfA
scientists, organized into six research divisions, study the origin,
evolution and ultimate fate of the universe.

ljk October 30, 2008 at 23:29

Dawn’s one year launch anniversary, just one month late.

From the Dawn Journal by Chief Engineer Dr. Marc Rayman:

September 27, 2008

Dear Dawnniversaries,

On the first anniversary of its departure from Earth, Dawn continues with what it has been doing for most of its time in space: with the greatest patience it is gently reshaping its orbit around the Sun with its ion propulsion system.

In its first year of travels, the spacecraft has thrust for a total of about 253 days, or 69% of the time. Dawn has been in powered flight for 85% of the time since the beginning of its interplanetary cruise phase in December 2007 and about 0.000000005% of the time since the Big Bang. While for most spacecraft, firing a thruster to change course is a special event, it is Dawn’s wont. All this thrusting has cost the craft only 67 kilograms (148 pounds) of its supply of xenon propellant, which was 425 kilograms (937 pounds) 1 year ago.

The thrusting so far in the mission has achieved the equivalent of accelerating the probe by 1.68 kilometers per second (3760 miles per hour). As the preceding log described, because of the principles of motion for orbital flight, whether around the Sun or any other gravitating body, Dawn is not actually traveling this much faster than when it launched. But the effective change in speed remains a useful measure of the effect of any spacecraft’s propulsive work. Having accomplished only one-eighth of the thrust time planned for its entire mission, Dawn has already exceeded the velocity change required by many spacecraft. (For a comparison with probes that enter orbit around Mars, visit the red planet yourself or refer to a previous log.)

Full article here:

http://dawn.jpl.nasa.gov/mission/journal_9_27_08.asp

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