New Horizons has now entered its planned quiet mode in preparation for its big day on July 14th as it makes its closest approach to Pluto at 7:49 AM EDT. We will not hear back from the spacecraft until 22 hours later around 9 PM EDT tomorrow. So what to expect tomorrow and the upcoming week? Emily Lakdawalla from the Planetary Society has a very detailed rundown that you can read here. Below is a general timeline of events.
Patience will be a virtue. New Horizons was built before the age of social media and is not sending Instagram pics. If all goes well, there will be a tremendous amount of data to download across the Solar System and that will take time. Keep in mind, even traveling at the speed of light, it will still take 4 1/2 hours for transmissions to reach Earth from Pluto.
New Horizons must either collect data or send it back to Earth. It cannot do both simultaneously. Consequently, New Horizons will spend July 14th diligently gathering data as it makes its closest approach to Pluto. And that is why New Horizons will be quiet for 22 hours until Tuesday night. Images should start to come in on Wednesday, July 15th. The mission timeline is as follows:
July 14th – 8:53 PM EDT, New Horizons scheduled to signal Earth the flyby was completed successfully.
July 15th – LORRI images (black & white) start to download along with data from ALEX, REX, and SWAP instruments (see below).
July 16th – first color images from Ralph instrument package to arrive.
July 20th – data will continue to download until this date. The data package received from July 15-20 is high priority science & public interest data and will represent a small percentage of total New Horizons data.
September 14th to November 16th – After a quiet period of 8 weeks, New Horizons will download compressed data set.
November 2015 to November 2016 – New Horizons downloads uncompressed data set.
A few of the highlights:
NASA TV will begin flyby coverage at 7:30 AM EDT on July 14th. You may watch online here.
New Horizons has an excellent Twitter feed.
The seven instruments at work are the following:
Long Range Reconnaissance Imager (LORRI) – this basically takes wide angle black & white shots of Pluto. NASA intends to release these images close to real time as they arrive.
Ralph – this is the instrument that takes color images of Pluto. It will take longer for NASA to release these images due to processing time. This instrument will map the surface of Pluto by taking stereo images and search for organic compounds among its many functions.
Alice – this is an ultraviolet spectrometer that will study the composition of Pluto’s atmosphere and attempt to detect an ionosphere (upper part of the atmosphere where particles are ionized by solar radiation).
Radio Science Experiment (REX) – will measure temperature and pressure in Pluto’s atmosphere. This instrument will be used after the flyby as it must be pointed towards the direction of Earth while in use.
Solar Wind Around Pluto (SWAP) – will measure the loss of Pluto’s atmosphere as a result of its weak gravity field. As the atmosphere escapes into space, it is ionized by solar radiation and carried away from Pluto by the solar wind.
Pluto Energetic Particle Spectrometer Science Investigation (PEPSSI) – this instrument basically performs the same function as SWAP, but measures higher energy atmospheric particles escaping Pluto into space. The combination of PEPSSI and SWAP will provide a comprehensive profile of Pluto’s atmospheric interaction with the solar wind.
Venetia Burney Student Dust Counter (SDC) – Venetia Burney was the eleven year old girl who named Pluto shortly after its discovery in 1930. This instrument has been measuring dust grain properties throughout New Horizons’ voyage and will provide a dust profile of the Solar System. This dust is a result of collisions of various Solar System bodies.
After the Pluto flyby, the mission team will select a Kuiper Belt object to head to. This flyby will take place in 2019. The voyage continues.
*Image at top of post is the mission operations center that will receive the data from New Horizons. NASA/Johns Hopkins University Applied Physics Laboratory/Southwest Research