Choose what to send without losing the question

Bandwidth — open definition describes a frequency range; bit rate counts transmitted bits per second. The two are related through modulation — open definition, noise and coding, but are not interchangeable units. Useful throughput can be lower than a quoted channel rate because framing, error protection and retransmissions consume capacity. Plan with the rate that actually delivers the intended data.

A raw image of one million pixels at 12 bits per pixel contains 12 million bits before headers or other overhead. Doubling the number of pixels doubles this raw volume at unchanged bit depth. Increasing bit depth preserves more possible numerical levels but also increases the number of bits to return.

Lossless compression — open definition allows the original digital values to be reconstructed exactly. Its achievable reduction depends on the data; a compressor cannot guarantee the same ratio for every image. Lossy compression — open definition intentionally removes information according to a chosen method. It may serve a particular visual task while altering features needed for another scientific question.

A thumbnail can help a team choose which full-resolution observations deserve priority. It should not silently replace the original measurement when subtle brightness differences matter. The processing history belongs with the product so another reader knows what could have been changed or discarded.

In a fictional four-minute contact with 0.5 megabits per second of useful throughput — open definition, the capacity is 120 megabits. Ten raw 12-megabit images fit exactly if that useful rate already accounts for overhead. This leaves no additional reserve for interruptions. A planning decision might send fewer images and preserve margin.

If tested lossless compression halves these particular files, each uses 6 megabits and 20 fit under the same simplified assumptions. That result is conditional on the actual ratio. A label saying “compressed” without a measured size is not enough to establish how much can be returned.

Suppose a team needs to distinguish two faint spectral features. A compression setting that blurs them together defeats the investigation even if the resulting file looks attractive. Compare processed and reference data using the scientific measurement, not only a casual glance at a display.

Keep selected originals, record transformations and choose priorities that reflect both scientific value and engineering needs. When storage fills faster than contacts empty it, the team must change acquisition, processing or return capacity. Compression is one choice in that system, not a substitute for a complete data budget.