a day trip to lake kussharo from sapporo

I plan to go to sapporo this Feb 2023. Can I make a day trip to lake kussharo from Sapporo by train/bus?
Thanks

The two trains you'd need to catch from Sapporo to Mashu station alone would be 6+ hours each way, (and that's assuming the seasonal buses start up again next year). Short of flying from Chitose to Membetsu and getting a rental car, practically impossible to do it in a day.

Public transport may not work in February due to bad weather.
For example, February 20th of this year
https://www.pref.hokkaido.lg.jp/ss/stk/saigai.html
On this day and the following day, many JR train services were suspended.
https://www3.nhk.or.jp/news/html/20220220/k10013493431000.html
Planes may be canceled depending on the weather, so it would be better to travel with plenty of time to spare.

Unsure of your intention to visit Kussharo lake in deep winter, not much to see and hardly any visitors at all. It is not impossible to do a day trip, it just sounds very rushed.
I visited a few years ago, but not on a day trip. I took a train to Mashu station and then a bus to my accomodation near the Kusharro lake. There were only 2 of us in the bus; the bus stopped for 15 minutes in Sunayu bus stop allowing ample time for us to enjoy the lake and the swans. As we were the only 2 passengers, the driver gave us a pleasant surprise, he made an impromptu stop at Kotan onsen, which turned out to be the highlight of the day! We felt so lucky to have met Takasaki- san, the driver, and were very grateful for his kindness. The bus stopped at our Hostel, and once we dropped off our luggage, we went back to enjoy the Kotan onsen, a magical place to visit in deep winter.