The equator of Vesta asteroid was photographed by the Dawn probe. High definition photos and descriptions are available on the project’s site.

Dark hill on the surface of the asteroid is of great interest to scientists. It looks dark on different photos, regardless of the shooting angle. It is likely that this is its natural color, and not a result of light and shadow effects. Scientists are discussing possible mechanisms of formation of the hill.

The photograph was taken on September 20, 2011, but only published now. When taking the image Dawn was at an altitude of 673 kilometers above the surface of the asteroid. The resolution of the photograph is about 66 meters per pixel.

Scientists working with the Dawn probe gave a report on the planetary science conference EPSC-DPS in French city of Nantes in early October. They reported that they have found the second largest mountain in the solar system on Vesta. The exact height of the peak, which is located on asteroid’s south pole, is not yet determined, but scientists believe it is “almost as high as the Olympus volcano on Mars” (the height of the volcano is 21 km).

Dawn probe was launched into space on September 27, 2007. It reached the orbit of Vesta – the second largest asteroid in the Solar System on July 16, 2011. Its mission will last approximately until 2015. During this time, the device should examine the relief of Vesta, its composition and determine the history of the asteroid.

In 2007 NASA launched its Dawn spacecraft on a mission to the solar system’s second biggest asteroid – Vesta. Vesta is located in the main Asteroid Belt and is approximately 117 million miles (188 million kilometres) from Earth. It has a circumference of 329 miles.

Dawn reached its destination last Saturday July 16. It transmitted information to confirm it entered Vesta’s orbit, but the exact time this milestone took place is not known. The time of Dawn’s capture depended on Vesta’s mass and gravity, which could only be estimated until this historic visit. The asteroid’s mass determines the strength of its gravitational pull. If Vesta is bigger than expected, its gravity is stronger, and consequentially it pulled the spacecraft into orbit quicker. If the asteroid is smaller than expected, its gravity is weaker and it would have taken Dawn longer to arrive at the orbit. With the spacecraft now in orbit, the researchers will be able to take more accurate readings of Vesta’s gravity and gather more accurate timeline information.

Dawn navigated toward the asteroid belt, a space rock-rich zone between the orbits of Mars and Jupiter, using gravitational energy from Mars and by firing its ion-powered thrusters.

Down spacecraft is the first human object to visit the asteroid. It is also the first spacecraft to orbit two solar system destinations beyond Earth. Dawn will hover about 9,900 miles above Vesta’s surface for a year and use two different cameras, a gamma-ray detector and a neutron detector to study the object. Next July, Dawn’s ion thrusters will fire up and slowly propel the spacecraft toward the dwarf planet Ceres – the largest object in the Asteroid Belt.

Dawn’s observations of Vesta will help scientists understand the earliest chapter of our solar system’s history. The findings will also be used for planning future manned missions to the Asteroid Belt.

Planetary scientists know very little about either Vesta or Ceres, but they suspect each has planet-like qualities. Vesta may have once had a molten core that oozes lava before going cold after a few million years. Ceres, meanwhile, may have an icy mantle and active mud volcanoes.

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[Images - NASA]

Few days ago we all witnessed the last space shuttle launch. The 30 years of shuttle history, starting with Columbia’s first flight in 1981 was a remarkable tale of achievement… and tragedy.

Based on an idea mooted by NASA’s German-born early space pioneer Wernher von Braun, the shuttle was a brilliant concept: a low-earth orbit, reusable spacecraft that could carry seven astronauts and almost 23,000 kg of cargo in its hold.

The shuttle’s ingenuity was its ability to dock with a space station orbiting Earth, deliver and retrieve goods, deploy satellites, carry out repairs, conduct experiments and return to Earth for repeated use by landing like a jet airliner.

The shuttle has performed these operations and returned safely 132 times by always had its limitations: as a low-orbit spacecraft it could never venture far from Earth. It was essentially a workhorse, not a vehicle for pursuing NASA’s broader objective of exploring deep space.

Cost was also an issue. The bill for each shuttle trip has remained close to $US1.5 billion despite early dreams of a drastically deduced sum once launches became a regular event.

NASA also faced dealing with an ageing fleet: Atlantis, the last shuttle in operation for last week’s final 135th launch, was commissioned in 1985. At some point, if the program had continued, NASA would have needed a fleet overhaul. The shuttle’s most nagging problem, however, had been a design flaw that contributed directly to the loss of two spacecraft and deaths of 14 astronauts.

In 1986, when a flame leak from the solid rocket booster ignited the external fuel tank, the shuttle Challenger exploded 73 seconds after lift-off, killing all seven crew on board.

And Columbia disintegrated during re-entry in 2003, also killing its crew of seven, after a mishap went undetected during lift-off: a chunk of foam insulation broke away from the external fuel tank and damaged a heat-shield tile on the shuttle’s wing.

These malfunctions were linked to having the shuttle attached to the sides of the external fuel tank, and two rocket boosters at launch time. The shuttle’s configuration – different to the old Apollo capsules – effectively guaranteed that if the fuel tank and rocket boosters experienced anomalies, the piloted shuttle was in immediate harm’s way.

The Columbia disaster forced a temporary shutdown of the program and ultimately its demise. President George W. Bush endorsed a replacement program in 2004 called Constellation that sought to gradually phase out the three surviving shuttles and redirect NASA funds into new missions: a resumption of moon landing and the first manned flight to Mars.
 

When Obama took over as President in 2009, the constellation program was behind schedule because of under-funding by Congress and technical difficulties associated with developing Ares 1, a proposed powerful new rocket. Obama’s solution, after a review uncovered a huge funding shortfall, was to cancel Constellation last year.

He kept the program’s long-term goal of deep space exploration using heavy lift rocket boosters but dumped moon landings. While short on detail, Obama says he expect manned missions to nearby asteroids by mid-2020’s and flights to orbit Mars by the mid-2030’s. “A landing on Mars will follow, and I expect to be around to see it,” he says.

[images - www.nasa.gov]

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