Tag Archives: space telescope

SpaceX has launched a space telescope!

In their first launch of a scientific satellite for NASA, SpaceX has placed the Transiting Exoplanet Satellite Surveyor (TESS) into Earth orbit and successfully recovered the first stage.  TESS is a follow-on to the massively successful Kepler space observatory.  Like Kepler, it will use the transit observation method to detect exoplanets, but unlike Kepler, it will be an all-sky survey, reliant upon an unusual orbit in a 2:1 resonance with the Moon (to avoid ever coming too close to the Moon and having the orbit disrupted).  The orbit is completely outside the Van Allen Belts, with a period of 13.7 days.  TESS will be able to downlink to ground stations during its perigees, at a distance of 108,000 km (about three times further away than the geosynchronous ring).  Although TESS has a nominal primary mission duration of two years, this orbit is expected to remain stable for decades, and the spacecraft will almost certainly be used to destruction like so many other NASA spacecraft, finding mission extension after extension until there is nothing more that it can do.

Falcon 9’s upper stage performed two burns, and then released TESS in a supersynchronous transfer orbit; the satellite itself will finish refining the orbit.  The upper stage has by now disposed of itself over the Pacific Ocean, and the payload fairing conducted a water landing as part of SpaceX’s effort to reuse the fairings.  (The company only has one fairing-catcher ship, Mr Steve, which is currently in California, unavailable for this mission.  So far, the closest a returning fairing has gotten to Mr Steve is a few hundred yards, so there is still some refinement needed.)

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Hard X-ray Modulation Telescope “Huiyan” blasts its way into space

As China advances forward its position in the international communities of spaceflight and astrophysics, it has placed the Hard X-ray Modulation Telescope (HXMT) “Huiyan” (Insight) into orbit aboard a Long March 4B rocket from Jiuquan Space Center in the Gobi Desert.  It’s a completely new type of x-ray telescope, devised because Chinese manufacturing presently does not have the capability to build the super-flat mirror surfaces required for building a traditional reflector-style x-ray telescope.  Necessity *is* the mother of invention, after all.  As implied by its name, the HXMT Huiyan uses a technique called demodulation that uses much simpler detectors.  Chinese scientists particularly hope to use this new instrument to study gamma ray bursts, which have become even more valuable targets now that gravity waves are detectable, as both can be caused by the same events.  The international astrophysics community will be able to use HXMT Huiyan’s data in conjunction with that from other X-ray detectors, such as the venerable Chandra X-ray Observatory, NuSTAR, Swift, Fermi, INTEGRAL, HETE-2, XMM Newton, and the upcoming Neutron Star Interior Composition Explorer, an instrument package that will be mounted on the exterior of the ISS later this year.

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JAXA declares Hitomi a loss

The Hitomi x-ray observatory, aka Astro-H, aka NeXT, that Japan launched just a couple of months ago was in its commissioning period when it abruptly lost contact with Earth on March 26.  JAXA has been struggling to regain control of the spacecraft, but sadly have now resigned themselves to its fate.  It is a total loss.  Furthermore, the intermittent garbled signals they thought they’d detected from it seem actually to have been radio interference in other signals unrelated to Hitomi, and not a true signal after all.

Ground observations in by visual and radio telescopes show that both of the spacecraft’s solar arrays have separated, and it has been tumbling since March 26.  It is very difficult to determine what went wrong, since most of the evidence is silently orbiting the Earth, but JAXA will be poring over manufacturing data, flight spares, and configuration data stored on Earth to try to figure it out.  Tentatively, it appears to have been a problem with the attitude control system, possibly in the software that controlled its orientation while passing through a magnetic anomaly which temporarily crippled the star tracker, which may have allowed the reaction control wheels to become oversaturated, further compromising its ability to control its orientation.  They believe tentatively that it got itself into a spin so violent that the solar arrays were literally ripped from the spacecraft.

This of course a very disappointing result.  Hitomi was to be a flagship x-ray observatory, carrying an instrument originally intended for Chandra, observing in frequencies that no other x-ray observatories currently cover.  It would cost tens of millions just to replace one of the instruments aboard the spacecraft; there’s no telling when, if ever, this mission could be reflown.

Goodbye, Hitomi.

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India launches its first space observatory!

This is a major step forward for India’s space program, on the same level as their successful Mars Orbiter Mission (Mangalyaan) in terms of the advancement and commitment to scientific research that it demonstrates.  The spacecraft is called Astrosat, and it is equipped to observe in ultraviolet, medium x-ray, and hard x-ray, with gamma ray detectors to enable it to study the gamma ray bursts.

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