NASA’s probe “New Horizon” traveled 3 Billion miles to get to Pluto. Data transmitted from Pluto takes 4.5 hours to reach the Earth simply due to distance.
How’s that for latency?
Weak signal strength is overcome by using two Traveling Wave Tube Amplifiers to amplify two differently-polarized signals before broadcasting via a 2m wide dish antenna. These transmitted X-band signals (8.0 – 12.0 GHz) are received on Earth by one of NASA’s three 230m deep space network dishes. Unfortunately, there is immense competition for time using any of these dishes, which further delays the transmission. These dual-polarized signals eventually reach one of these dishes and combine to produce a stronger signal, which allows for a better data rate.
Even with this technique however, the transmission speed is just 1 kilobit per second!
Image: NASA
Another transmission deficit lies in the structure of the probe. The instruments are all body-mounted, which means it must be angled a specific way to observe and collect data which is in opposition to its appropriate angle for data transmission. It can’t observe and transmit simultaneously.
New Horizon is also running into power issues, there is not enough power to run both Tube Amplifiers and the miscellaneous data collection instruments on-board. Additionally, data storage only amounts up to 8 gigabytes. They don’t want to run out of power, neglect data collection, fall behind on transmission or cap out on storage, which means NASA needs to balance all of this carefully.
With all of these transmission conditions, NASA projects 16 months to transmit all the data back to Earth!
