Tag Archives: space

SOFTWARE UPDATE DESTROYS $286 MILLION JAPANESE SATELLITE

The Japanese X-ray telescope Hitomi has been declared lost after it disintegrated in orbit, torn apart when spinning out of control. The cause is still under investigation but early analysis points to bad data in a software package pushed shortly after an instrument probe was extended from the rear of the satellite. JAXA, the Japanese space agency, lost $286 million, three years of planned observations, and a possible additional 10 years of science research.

Hitomi, also known as ASTRO-H, successfully launched on February 17, 2016 but on March 26th catastrophe struck, leaving only pieces floating in space. JAXA, desperately worked to recover the satellite not knowing the extent of the failure. On April 28th they discontinued their efforts and are now working to determine the reasons for the failure, although a few weeks ago they did provide an analysis of the failure sequence at a press conference.

hitomi Japanese X-ray telescope
hitomi Japanese X-ray telescope

On March 26th, the satellite completed a maneuver to point at the galaxy Markarian 205. The Attitude Control System (ACS) began using the Star Tracking (STT) system data to control the position of the satellite. The STT at this point should have updated another position monitoring system, the Inertial Reference Unit (IRU). This may not have occurred.

At the time, the satellite was passing the South Atlantic Anomaly. This is important for two reasons. First, it placed Hitomi in a communications blackout region which meant there was no active ground monitoring of the situation (human intervention might have prevented the catastrophic failure). Second, the belts of radiation encircling the Earth dip low in this region so particle density is higher than in other parts of the orbit. High energy particles may have disrupted the onboard electronics.

The STT and IRU disagreed on the attitude of the satellite. In this case the IRU takes priority, but its data apparently was wrong, reporting a rotation rate of 20 degrees per hour, which was not occurring. The satellite attempted to stop this erroneous rotation using reaction wheels. The satellite configuration information uploaded earlier was wrong and the reaction wheels made the spin worse.

The satellite now went into “Safe Hold” mode and thrusters were called upon to stop the rotation. Using the same erroneous configuration information they increased the spin further causing the satellite’s rotation to exceed design parameters. Parts, like the solar sails, came off. In all, at least 5 pieces were observed in addition to the main body. Some reports indicate there may be as many as 10 pieces with 2 larger and 8 smaller pieces continuing in orbit. It’s likely that all ten pieces separated originally but their close proximity prevented visual and radar images from seeing them as separate entities.

In satellites, the STT typically gets a good fix and sends the data to the IRU. The IRU uses the data to set its current reading and to measure how far it drifted since the last update. After calculating the drift it uses drift adjustments to compensate for the future drift. Clearly if the compensation calculation is wrong the future readings are going to be wrong. This appears to have played a role since the ACS attempted to correct a rotation that didn’t exist. The erroneous configuration information led the ACS to aggravate, not correct, the rotation.

The hardware was built to study hard X-ray sources in the Universe. X-ray satellites like the Hitomi are not hindered by dust clouds that obscure visual instruments. Previous satellites have greatly expanded our knowledge of the Universe, with Japan as the leader in the technology.

Japan’s first successful X-ray satellite, Hakucho, was launched in 1979. Other successful launches followed in ’83, ’87, and ’93. Launches in ’76 and 2000 failed. Their most recent X-ray satellite, Suzaka, launched in 2005, was just decommissioned in 2015 due to deterioration of batteries and other components. It was hoped that Hitomi would see similar utility but that hope has now been extinguished.

[Images from JAXA web site and reports.]

Europe and Russia launch joint Space Mission to Mars

Europe and Russia launch joint Space Mission to Mars

The Trace Gas Orbiter and Schiaparelli blasted off at 0931:42 GMT (5:31:42 a.m. EDT) from Complex 200 at the Baikonur Cosmodrome. Shortly after the fourth burn, ExoMars separated from Breeze-M and deployed its solar panels.

Luzin predicted the mission’s presumed success is likely to have benefits for Russia’s space program, which is struggling to stay competitive. “The second part of the ExoMars mission may be delayed to 2020”, said Igor Komarov, the chief of Roscosmos. In 2013, United States’ Beagle Probe disappeared, and ESA is trying to avoid these kinds of setbacks.

Dr Manish Patel, from the Open University, who is in charge of TGO’s ozone-mapping ultraviolet (UV) spectrometer instrument, said: “This is a fantastic mission, massive”.

TGO will photograph the Red Planet and analyse its air, splitting off from the lander dubbed Schiaparelli days before entering Mars’ atmosphere. Its task is to study life-hinting gases, such as methane, which is linked to life on Earth.

Its main job will be to test the descent and landing technology for ExoMars 2018, the next stage of the mission which will send a British-built rover to Mars in two years’ time.

The 660kg Schiaparelli will land on the Martian surface to collect meteorological and other types of data.

ESA said the rover landing “remains a significant challenge” however.

ExoMars, which cost the European Space Agency alone 1.3 billion euros ($1.44 billion), is the first interplanetary mission jointly undertaken by ESA and Roscomsos.

KAZAKHSTAN – Two robotic spacecraft on Monday began a seven-month journey to Mars as part of a European-Russian unmanned space mission to sniff out leads to life on the Red Planet. The second is planned for launch in 2018 and is a rover and surface science platform.

The joint investigation will involve the search for natural gases that scientists believe may be a sign of human life on Mars, The Australian reported.

“It’s been a long journey getting the first ExoMars mission to the launch pad, but thanks to the hard work and dedication of our global teams, a new era of Mars exploration is now within our reach”, Johann-Dietrich Woerner, director general of the European Space Agency, said in a statement.

Neither the ESA nor Roscosmos has the best track record when it comes to Martian missions, and for now, both space agencies are breathing a huge sigh of relief.

Traffic around Mars is about to get a bit heavier.

ExoMars is made up of 2 phases. Today’s launch brought along 2 different modules that make up the first phase: the Trace Gas Orbiter and the Entry, Descent and Landing Demonstrator Module known as “Schiaparelli”.