The solar conjunction of Mars occurs approximately every 25 months, interfering with communication with Mars missions. In 2023, Mars will pass straight behind the Sun, triggering a total communication blackout for about one and a half days. This occasion highlights the challenges in interplanetary communication and the requirement for innovative preparation and technology.
The area between Earth and Mars is usually buzzing with science information, telemetry, and commands racing to and from practically a dozen missions at the Red Planet. For roughly one and a half days this November, communication between the planets will fall quiet as Mars passes behind the Sun.
Tis the Season for Conjunction
Solar combination for Mars occurs approximately once every 25 months. Throughout conjunction, Mars is found on the opposite side of the Sun from Earth.
Around the time of combination, the radio signals utilized to send out commands from Earth to the spacecraft and to get signals from the spacecraft can be disrupted by the Suns active environment– the solar corona.
This image was acquired using the Visual Monitoring Camera (VMC) on ESAs Mars Express spacecraft on November 10, 2023, at 06:28:27 UTC. It was drawn from an altitude of 7690.16 km above Mars, during Mars Express orbit number 25073 and the 2023 Mars solar conjunction. Credit: ESA, CC BY-SA 3.0 IGO
The duration of time throughout which interactions are considerably disrupted depends upon the size and power of a Mars spacecrafts interaction equipment, but typically occurs while the angle in the sky in between the Sun and Mars as seen from Earth is within 3– 4 °.
In 2023, this duration lasts from early November to early December.
As an outcome of the disturbance, objective controllers cant reliably send commands to, or get data from their spacecraft. Unique safety measures have to be taken.
During the conjunction season, the Suns corona hinders the radio signals used to interact with missions at Mars.Credit: ESA/AOES Medialab, CC BY-SA 3.0 IGO
Getting Ready For Communication Challenges
For ESAs Mars Express and ExoMars Trace Gas Orbiter (referred to as MEX and TGO, because we enjoy our acronyms), this implies uplinking all the vital instructions the spacecraft would need to operate without any contact from Earth for the entire period. Thats 3 or 4 weeks of commands when we usually send up just one week at a time.
Naturally, these conjunctions likewise impact the missions of other space companies– and this example isnt unique to Mars.
When seen from Earth throughout the solar combination of 2023, created view of Mars behind the Sun. During conjunction, it is tough or perhaps difficult to exchange information in between spacecraft at Mars and ground stations in the world as the solar corona or, seldom, the disc of the Sun itself, interfere or obstruct radio interaction. Credit: ESA, CC BY-SA 3.0 IGO
Ground Stations to Full Power!
Due to the disruption from the Suns atmosphere throughout combination season, we have to lower the amount of information we exchange with MEX and TGO.
We cut the quantity of data that we uplink to MEX, for example, below 2000 bits per 2nd to simply 250, and reduce the quantity of data that MEX sends out down to Earth to just 300 bits per second.
We also set our Estrack ground stations to maximum transmission power to ensure our spacecraft hears us clear and loud in spite of the disruption, i.e., we use a louder voice however state less words.
View from the web cam at ESAs deep space ground station in New Norcia, Western Australia, as the antenna communicates with ESAs Mars Express spacecraft on November 10, 2023. Credit: ESA, CC BY-SA 3.0 IGO
This limits the type of information that MEX can send out to its operators in the world to housekeeping data– health status and telemetry– and is too low for MEX to send out any science information.
Like a diver holding their breath, any information gathered by MEXs instruments during the conjunction duration must be kept in the minimal onboard memory up until the duration is over.
What makes the 2023 conjunction unique?
Mars Express reached the Red Planet on December 25, 2003, and is one of Europes longest-serving missions. The group celebrated 20 years since launch this summer with the first-ever live webcast from another world.
This will be MEXs tenth solar conjunction and TGOs 3rd. However, as the orbits of Mars and Earth have a little different inclinations, Mars doesnt generally pass straight behind the Sun.
Twenty years earlier, on June 2, 2003, ESAs Mars Express orbiter released and began its journey to the Red Planet– Europes first-ever mission to Mars. Credit: ESA
The 2023 conjunction is unusual because it will be the first time that Mars passes behind the disc of the Sun given that the 2 ESA spacecraft got here.
While Mars is behind the Sun, for roughly one and a half days on 17– 18 November, communication with MEX and TGO wont just be restricted, itll be difficult..
These windows of restricted or impossible interaction in between Earth and Mars will present a challenge for future human inhabitants, too.
Are You Worried?
” At the beginning of the objective, the group was very cautious about combinations,” states James Godfrey, Spacecraft Operations Manager for Mars Express. “If something goes seriously wrong during the conjunction period, it might be hard to recuperate the spacecraft till its over.
” We utilized to suspend all science operations. But, for many years, weve only ever knowledgeable small interruptions.”.
The orbits of the inner worlds on November 17 and 18, 2023. Mars and Earth are situated on opposite sides of the Sun, marking the 2023 solar conjunction. Credit: ESA, CC BY-SA 3.0 IGO.
” In 2019, we discovered that we can continue utilizing a few of MEXs instruments in a minimal way, as long as all commands are submitted before the season starts, and all science information are saved on board till the season ends.
” Originally, planning for combinations was a really manual procedure,” says James Godfrey. “But over the years, its become mostly routine.”.
Peter Schmitz, Spacecraft Operations Manager for Trace Gas Orbiter, adds: “With its larger interactions antenna and data storage capacity, TGO is able to continue with its information relay activities for Mars surface possessions throughout the conjunction period– even when Mars is straight behind the Sun– and prepare to downlink all of the kept information to Earth when it is when again safe to do so.”.
The solar conjunction of Mars takes place approximately every 25 months, interfering with communication with Mars objectives. It was taken from an altitude of 7690.16 km above Mars, throughout Mars Express orbit number 25073 and the 2023 Mars solar conjunction. Produced view of Mars behind the Sun when viewed from Earth during the solar conjunction of 2023. During conjunction, it is tough or even impossible to exchange data in between spacecraft at Mars and ground stations on Earth as the solar corona or, rarely, the disc of the Sun itself, interfere or block radio interaction. Mars and Earth are located on opposite sides of the Sun, marking the 2023 solar combination.