Between now and early December, radio alerts used to ship instructions from Earth to Mars spacecraft – and to obtain alerts from the spacecraft – will be disturbed by the sun’s corona, its outermost environment. So communications from Earth with spacecraft, landers, rovers and future people on the crimson planet are at the moment restricted. Reprinted from the European Space Agency. Edits by EarthSky.
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Mars spacecraft fall silent
The space between Earth and Mars is often buzzing with science information, telemetry and instructions racing to and from virtually a dozen missions on the crimson planet. However for roughly 1 1/2 days, communication between the planets will fall silent as Mars passes behind the sun on November 18.
Solar conjunction for Mars happens roughly as soon as each 25 months. Throughout conjunction, Mars is positioned on the other aspect of the sun from Earth.
Across the time of conjunction, the radio alerts used to ship instructions from Earth to the spacecraft and to obtain alerts from the spacecraft will be disturbed by the sun’s energetic environment, the solar corona.
The time period throughout which communications are considerably disturbed will depend on the dimensions and energy of a Mars spacecraft’s communication tools. Nevertheless it sometimes takes place whereas the angle within the sky between the sun and Mars as seen from Earth is inside 3 to 4 degrees.
In 2023, this era lasts from early November to early December.
No earthly directions for Mars spacecraft
On account of the disruption, mission controllers can’t reliably ship instructions to, or obtain information from, their spacecraft. Particular precautions need to be taken.
For ESA’s Mars Express and ExoMars Trace Gas Orbiter (generally known as MEX and TGO, as a result of we take pleasure in our acronyms), this implies uplinking all of the vital directions the spacecraft would wish to function with none contact from Earth for your complete interval. That’s three or 4 weeks of instructions after we usually ship up just one week at a time.
After all, these conjunctions additionally have an effect on the missions of different space businesses, and this sort of factor isn’t unique to Mars.
Floor stations to full energy!
As a result of disturbance from the sun’s environment throughout conjunction season, we now have to scale back the quantity of knowledge we change with MEX and TGO.
We lower the quantity of knowledge that we “uplink” to MEX, for instance, down from 2000 bits per second to only 250, and cut back the quantity of knowledge that MEX sends right down to Earth to as little as 300 bits per second.
We additionally set our Estrack ground stations to most transmission energy to ensure our spacecraft hears us loud and clear regardless of the disturbance, i.e., we use a louder voice however say fewer phrases.
This limits the type of data that MEX can ship to its operators on Earth to “housekeeping” information – well being standing and telemetry – and is simply too low for MEX to ship any science information.
Like a diver holding their breath, any information gathered by MEX’s devices throughout the conjunction interval should be saved within the restricted onboard reminiscence till the interval is over.
What makes the 2023 conjunction particular?
Mars Categorical arrived on the crimson planet on December 25, 2003, and is one in every of Europe’s longest-serving missions. The workforce celebrated 20 years since launch this summer season with the 1st-ever reside webcast from one other planet.
This will likely be MEX’s tenth solar conjunction and TGO’s third. Nonetheless, because the orbits of Mars and Earth have barely completely different inclinations, Mars doesn’t often cross immediately behind the sun.
The 2023 conjunction is uncommon in that it will likely be the primary time that Mars passes behind the disk of the sun because the two ESA spacecraft arrived.
Whereas Mars is behind the sun, for roughly 1 1/2 days on November 17-18, communication with MEX and TGO gained’t simply be restricted, it’ll be inconceivable.
These home windows of restricted or inconceivable communication between Earth and Mars will pose a problem for future human settlers, too.
Are you apprehensive?
James Godfrey, Spacecraft Operations Supervisor for Mars Categorical. mentioned:
Firstly of the mission, the workforce was very cautious about conjunctions. If one thing goes severely fallacious throughout the conjunction interval, it could possibly be tough to get well the spacecraft till it’s over.
We used to droop all science operations. However, through the years, we’ve solely ever skilled minor disruptions.
In 2019, we found that we will proceed utilizing a few of MEX’s devices in a restricted method, so long as all instructions are uploaded earlier than the season begins, and all science information are saved on board till the season ends.
Initially, planning for conjunctions was a really handbook course of. However through the years, it’s develop into largely routine.
Peter Schmitz, Spacecraft Operations Supervisor for Hint Fuel Orbiter, added:
With its bigger communications antenna and information storage capability, TGO is ready to proceed with its information relay actions for Mars floor belongings all through the conjunction interval – even when Mars is immediately behind the sun – and put together to downlink the entire saved information to Earth when it’s as soon as once more secure to take action.
Backside line: Photo voltaic conjunction for Mars occurred yesterday, November 18, 2023. That’s when Mars was most immediately behind the sun for this 25-month interval. In 2023, the season of Mars’ conjunction takes place between November 5 and December. Throughout this era, information change between Mars spacecraft and Earth is proscribed.
