From a NASA fun facts website How do satellites communicate?:

How do satellites communicate?

Satellites communicate by using radio waves to send signals to the antennas on the Earth. The antennas then capture those signals and process the information coming from those signals. Information can include:

  • scientific data (like the pictures the satellite took),
  • the health of the satellite, and
  • where the satellite is currently located in space.

My question is: What network does the Chandra X-ray Observatory satellite use in its communication?


1 Answer 1


As mentioned in one of the comments to the question, CXO uses the Deep Space Network for communication.

This appears to be reliable resource for the CXO. According to this and this

... description
Antennas Two low-gain, conical log sprial antennas provide spherical coverage
Frequencies Transmit 2250 megahertz (MHz)
Receive 2071.8 MHz
Command Link 2 kilobits persecond (kbps)
Data Recording Solid-state recorder; 1.8 gigabits (16.8 hours) of recording capacity
Downlink Options Selectable rates from 32 to 1024 kbps Downlink data includes pre-recorded engineering and science instrument data interleaved with real-time data
Downlink Operations Data downloaded to Earth typically every 8 hours
Contingency Mode 32kbps

According to this

Commands for executing the observing plan are sent from the OCC to one of the three stations in Spain, Australia and California that make up NASA's Deep Space Network, for relay to the orbiting spacecraft.

After carrying out the planned observations, the Chandra spacecraft transmits scientific data and monitoring information to the OCC, via the Deep Space Network, approximately every eight hours.

From here

The communications, control, and data management system is the nerve center of the Observatory. It keeps track of the position of the spacecraft in its orbit, monitors the spacecraft sensors, receives and processes commands from the ground for the operation of the Observatory, and stores and processes the data from the instrument so that it can be transmitted to the ground.

Chandra has two low gain antennae, either one of which may be used for two-way communications with Chandra's Operations Control Center (OCC). All ground commands to and from Chandra along with telemetry data — sent through a set of three NASA ground stations constituting its Deep Space Network — are routed through one of these antennae, typically about once every eight hours.

  • 1
    $\begingroup$ "This appears to be reliable resource for the CXO", it currently is, but there are a lot of concerns about the aging network. The Deep Space Network is often pushed to its maximum capacity. The situation got some attention during the Artemis I mission when the several cubesats that were along for the ride required additional antenna time due to struggles that they were having. This caused JWST and other assets to have to give up bandwidth. Plans to replace the old 70 meter antennas at each location with an array of newer 34 meter antennas have been shelved for now due to underfunding. $\endgroup$ Sep 21, 2023 at 12:35

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