Hubble returned to operational service, showcases exoplanet’s second atmosphere
The Hubble Space Telescope recently garnered headlines for a software anomaly that caused the iconic… The post Hubble returned to operational service, showcases exoplanet’s second atmosphere appeared first on NASASpaceFlight.com.
The Hubble Space Telescope recently garnered headlines for a software anomaly that caused the iconic observatory to enter safe mode as its control teams worked to successfully restore the telescope to operational status.
While Hubble is showing its age, scientists using the observatory are nonetheless continuing to produce incredible scientific discoveries, including a recent announcement surrounding an exoplanet 41 light years away that is on its second atmosphere.
In May 2009, Space Shuttle Atlantis performed the fifth and final servicing mission to the Hubble Space Telescope, which was already showing signs of degradation in the seven years that had passed since its previous upgrade.
Now 12 years on from that final servicing mission, the telescope is showing its age again, most recently with a safe mode event that occurred on Sunday, 7 March at 04:00 EST/09:00 UTC when a software error was detected inside the telescope’s main computer.
Hubble’s control teams quickly isolated the cause of the error to a recent upload to help the telescope compensate for fluctuations in one of its gyroscopes — which are themselves vital to the rock-solid pointing ability of the observatory.
Moreover, a different issue stemming from the safe mode revealed another issue with the telescope, specifically with its aperture door. This door must remain open for scientific observations, but is designed to close in the event the telescope enters safe mode. This is done to protect the sensitive optics packages from potential damage if the telescope were to drift to a Sun-pointing orientation.
However, the safe mode event of Sunday, 7 March did not result in the aperture door closing, which led teams down a failure analysis which revealed that the primary motor that closes and opens the door was no longer working.
Control teams switched to the backup motor and were able to verify proper operation of the aperture door. The backup motor will now serve as the primary motor.
By Saturday, 13 March, Hubble was back in full operation as teams reactivated Wide Field Camera 3 — the last of the instruments to be brought back online.
Nonetheless, the iconic telescope is aging, and the day will come when a failure will present itself. A failure which cannot be overcome.
The telescope was designed to be serviced and upgraded by the Space Shuttle fleet. Without that lifeline, the observatory’s remaining time will be determined by the continued operations of its systems.
Atmospheric drag is also lowering Hubble slowly over time. Unless the spacecraft were to be re-boosted, it will naturally reenter the atmosphere sometime in the 2030s — with the exact date dependent on solar activity, which affects the thickness of Earth’s atmosphere and thus the drag imparted to Hubble that lowers its altitude.
While unlikely, the possibility remains that a Crew Dragon or Orion mission could service the telescope again.
In June 2020, John Grunsfeld, former astronaut/Hubble servicing spacewalker and former associate administrator for NASA’s Science Mission Directorate, encouraged a study on a such a mission, saying: “I wouldn’t preclude the possibility, because we have the capability coming online in the next ten years, that you could send a repair mission up to Hubble. We have the technology to go back to Hubble.”
The remarks were not official, though Grunsfeld did present notional mission architecture for such a flight.
Of note, neither NASA nor SpaceX (the only two organizations currently with spacecraft to perform such a mission – Orion being NASA’s internal ship and Crew Dragon from SpaceX being the only currently operational crew orbital transportation vehicle for the U.S.) have made any comment regarding a feasibility study or a potential future mission to Hubble.
An exoplanet on its second atmosphere?
Just 41 light years away lies a 4.5 billion year old, Earth-sized, terrestrial world called GJ 1132 b.
For Earth-like exoplanet hunters, that’s where the excitement ends. However, to others in the exoplanet field, that’s where the excitement begins.
Because this exoplanet is nothing like Earth. It orbits its host star every 1.5 days and is tidally locked with that star (a red dwarf). What’s more, when scientists used the Hubble Space Telescope to examine this exoplanet, they discovered an atmosphere composed of molecular hydrogen, hydrogen cyanide, methane, and aerosol haze.
Not exactly something a human would want to breathe, but the simple fact the GJ 1132 b has an atmosphere is what makes the exoplanet so fascinating. Because it wasn’t expected to have one.
“We first thought that these highly irradiated planets could be pretty boring because we believed that they lost their atmospheres,” said Raissa Estrela of NASA’s Jet Propulsion Laboratory (JPL), co-author of the study to be published in a forthcoming issue of The Astronomical Journal.
“But we looked at existing observations of this planet with Hubble and said, ‘Oh no, there is an atmosphere there.’ It’s super exciting because we believe the atmosphere that we see now was regenerated, so it could be a secondary atmosphere.”
Based on observations from Hubble and current models and theories of planetary formation, GJ 1132 b likely began life as a several-times Earth diameter gaseous planet, falling into a category known as sub-Neptune.
The massive planet’s atmosphere was quickly irradiated by its host star in a short period of time that left behind the planet’s terrestrial core that is roughly the same size as Earth.
So if its atmosphere was stripped away by its star’s radiation, how does it have an atmosphere today?
The terrestrial rock, or core of the gas giant, left behind after its atmosphere was removed, is significantly affected by a process known as tidal heating, where the gravitational tugs of war between the red dwarf star and at least one other exoplanet in the system on GJ 1132 b cause it to expand and contract — which in turn transfers that energy into the planet’s core in the form of heat which sustains a molten interior.
Containing that interior is a much cooler and very thin crust — so thin that it cannot support volcanic structures, meaning the exoplanet’s surface is likely cracked like an eggshell. Those cracks allow the release of hydrogen and other gases.
The planet’s gravity then keeps those gasses contained: the atmosphere observed today.
“How many terrestrial planets don’t begin as terrestrials?” asked Mark Swain of JPL, lead author of the paper. “Some may start as sub-Neptunes, and they become terrestrials through a mechanism that photo-evaporates the primordial atmosphere.”
While Hubble itself is not powerful enough to directly image the exoplanet, an upcoming NASA observatory, the James Webb Space Telescope, does possess the ability to observe GJ 1132 b in finer detail, specifically in the infrared band which may allow scientists to see the exoplanet’s surface as well as potential magma pools or active volcanism.
The James Webb Space Telescope is currently undergoing final testing and check out at Northrop Grumman’s Redondo Beach, California facility near Los Angeles. It will be shipped to its launch site in the coming months and currently remains on track for liftoff on top of an Ariane 5 rocket from Kourou, French Guiana in South America on 31 October 2021.
(Lead image credit: NASA)
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